Cannabis in Aotearoa New Zealand

The Prime Minister has asked Juliet to provide an accessible summary of the evidence to inform the cannabis referendum. Our expert panel has been charged with pulling together as much information as we can about the impacts of cannabis, and to present it in a way that is easy to understand for voters.

Aspects of the work will include, but not necessarily be limited to, analysing the impacts of cannabis use in the current legal framework, what changes have occurred overseas when access to cannabis is decriminalised or legalised,  the confidence level around the evidence base, and how applicable it is to Aotearoa New Zealand.

For information on the referendum question and the proposed bill, visit the New Zealand Government cannabis referendum site

Values Statement

The work of the panel will be characterised by rigour, respect, openness, collaboration, inclusivity and integrity. We recognise the significance of culture, including te Tiriti o Waitangi. We strive to acknowledge our biases and limitations, synthesise the evidence and expose the gaps.

Project details

The cannabis project is underway. We are currently analysing and collating the evidence base to summarise and present in a way that is easy to understand for voters. This information will be uploaded to this page as we go – so check back for updates.

Project scope

The terms of reference set the project scope. The evidence base will fall within the following five workstreams:

  • What are the personal and societal harms from recreational cannabis use?
  • What are the potential non-medical benefits of recreational cannabis use? (e.g. reduction in costs for the justice system)
  • What is the evidence base surrounding impacts of decriminalisation of recreational cannabis use, and how might the impacts be monitored?
  • What is the evidence base surrounding the impacts of legalisation of recreational cannabis use, and how might the impacts be monitored?
  • What is the confidence level around the evidence base and where are there important gaps in
    our knowledge?

Download the terms of reference (PDF, 116KB)


Panel members and OPMCSA staff at the first panel meeting in September 2019. From left to right: Juliet Gerrard, Joseph Boden, Tracey McIntosh, David Newcombe, Hinemoa Elder, Chris Wilkins, Khylee Quince, Benedikt Fischer, Doug Sellman, Michelle Glass, Tamasailau Suaalii.

University of Otago

Professor Joseph Boden is a member of the Department of Psychological Medicine at the University of Otago, Christchurch. Originally earning a PhD in experimental social psychology, Joe held university lectureships in the UK and Australia before coming to New Zealand in 2002. Since 2005 he has been employed as a researcher on the long-running Christchurch Health and Development Study (CHDS), a longitudinal study of over 1000 New Zealanders born in Christchurch in mid-1977. In 2015 Joe was appointed Deputy Director of the CHDS, and in 2019 he was appointed Director of the CHDS. His research interests include the psychosocial causes and consequences of substance use, abuse, and dependence; mental health and substance use epidemiology; and the social and psychological determinants of maladaptive behaviour including aggression and violence, among other topics.

Visit Joseph’s university profile page

University of Auckland

Ko Pārengarenga te moana
Ko Tawhitirahi te maunga
Ko Awapoka te awa
Ko Te Aupouri, ko Ngāti Kurī, ko Te Rarawa, ko Ngāpuhi nui tonu oku iwi
Ko Hinemoa taku ingoa

Hinemoa Elder is a Fellow of the Royal Australia and New Zealand College of Psychiatrists and has been a consultant child and adolescent psychiatrist since 2006. Hinemoa is the Māori Strategic Leader for the Centre of Research Excellence (CoRE) for the Ageing Brain. In addition to her initial medical qualifications, Hinemoa has a PhD (Massey University, 2012) and is former HRC Eru Pomare Post-Doctoral Fellow (2014–18) in which she developed a novel recovery approach grounded in Te Ao Māori (Māori world view), for Māori with traumatic brain injury, their whānau (extended families) and professionals which is now being used in community rehabilitation services. She continues to work clinically as a neuropsychiatrist and youth forensic psychiatrist. She is an expert in the areas of psychological trauma and cultural psychiatry. She also currently works at the Child and Family Unit, Starship Hospital.

Hinemoa has served on several Ministry of Health reference groups. She is a deputy psychiatrist member of the NZ Mental Health Review Tribunal and a Specialist Assessor under the Intellectual Disability (Compulsory Care and Rehabilitation) Act 2003. She is a member of the International Science Advisory Board to the National Science Challenge ‘E tipu e rea, a better start’.

Visit Hinemoa’s university profile page

University of Auckland

Benedikt Fischer is the inaugural Hugh Green Foundation Chair in Addiction Research and Professor in the Schools of Population Health & Pharmacy at the University of Auckland. He holds additional academic appointments with the Department of Psychiatry, University of Toronto, Canada; the Centre for Applied Research in Mental Health & Addiction (CARMHA), Simon Fraser University, Vancouver, Canada; and the Department of Psychiatry, Federal University of Sao Paulo (UNIFESP), Brazil. Prior to moving to New Zealand in 2018, Benedikt held senior academic appointments in Canada, as senior scientist at the Centre for Addiction & Mental Health and the Addiction Psychiatry Chair at the University of Toronto (until 2018) and as the CIHR/PHAC Applied Public Health Research Chair and Director of CARMHA at Simon Fraser University, Vancouver (2008–2014).

Benedikt’s scientific work focuses on the social, behavioural and health outcomes of, and evidence-based prevention and treatment interventions for psychoactive substance use and related co-morbidities (e.g. mental health, pain, infectious disease) in an interdisciplinary, public health-oriented framework. His scientific work is strongly geared towards knowledge translation for improved interventions, systems and policy. For more than two decades, he has made major scientific contributions to public health-oriented cannabis control and interventions, including as lead-author of the internationally adopted ‘Lower-Risk Cannabis Use Guidelines (LRCUG)’.

Benedikt acted as Senior Science Advisor to the Canadian government for the development of its cannabis legalisation framework, and has advised other governments (e.g. Uruguay) on cannabis and health policy issues. He is a co-author of several international books: ‘Drug Policy & the Public Good’ (Babor et al., 2018) and ‘Cannabis Policy: Moving Beyond Stalemate’ (Room et al., 2010). He has served in science advisory roles for preeminent institutions (e.g., CIHR’s Institute of Neuroscience, Mental Health and Addiction; the Mental Health Commission of Canada, Health Canada). Benedikt is a frequent and sought-after expert speaker and commentator to academic, media and general public audiences on his topics of expertise.

Visit Benedikt’s university profile page

University of Otago

Michelle Glass took up the position of Head of the Department of Pharmacology and Toxicology and the University of Otago in July 2018. This appointment came after 17 years at the University of Auckland, including six years as the Head of Pharmacology and Clinical Pharmacology. As a molecular pharmacologist, Michelle’s research focuses on the expression, function and molecular pharmacology of the cannabinoid receptors and their potential role in treatment of neurodegenerative diseases.

Following her PhD, in which she mapped the then newly discovered cannabinoid CB1 receptor in the human brain, she worked on cannabinoid receptor signalling as a postdoctoral fellow at the National Institutes of Health in Bethesda, Maryland for five years before returning to New Zealand in 2000 to take up a role as a lecturer (and researcher) within the Department of Pharmacology at the University of Auckland. She has published over 90 papers on cannabinoids, and numerous book chapters.

Her contributions to the field have been acknowledged by an early career award from the International Cannabinoid Research Society in 2009 and by election to President of this society in 2015.

Visit Michelle’s university profile page

University of Auckland

Tracey McIntosh is of Ngāi Tūhoe descent and is Professor of Indigenous Studies and co-head of Te Wānanga o Waipapa (School of Māori Studies and Pacific Studies) at the University of Auckland. She was the former co-director of Ngā Pae o te Māramatanga – New Zealand’s Māori Centre of Research Excellence. She previously taught in the sociology and criminology programme at the University of Auckland. She was a Fulbright Visiting Lecturer in New Zealand Studies at Georgetown University in Washington D.C. and lectured at the University of the South Pacific in Fiji. She has sat on a number of assessment panels including PBRF panels (Māori Knowledge and Development and Social Sciences), the Marsden Social Science panel, Rutherford Discovery, James Cook Fellowship and Health Research Council panels. In 2012 she served as the co-chair of the Children’s Commissioner’s Expert Advisory Group on Solutions to Child Poverty.​ In 2018–2019 she was a member of the Welfare Expert Advisory Group and Te Uepū Hapai i te Ora- The Safe and Effective Justice Advisory Group. She sits on a range of advisory groups and boards for government and community organisations. She currently delivers education and creative writing programmes in prisons.​

Her recent research focused on incarceration (particularly of Māori and Indigenous peoples), gang whānau issues and issues pertaining to poverty, inequality and social justice.

Visit Tracey’s university profile page

University of Auckland

Associate Professor David Newcombe is Academic Director of postgraduate addiction programmes and Head of the Section of Social and Community Health in the School of Population Health, and Associate Director of the Centre for Addiction Research. He has been working in the addiction sector for more than 20 years in various clinical and research roles both in Australia and New Zealand. Prior to moving to New Zealand, David was Senior Project Manager at the World Health Organization (WHO) Collaborating Centre for Research in the Treatment of Drug and Alcohol Problems at the University of Adelaide. Here, he managed an international multisite evaluation of opioid pharmacotherapies for the treatment of opioid dependence and the Australian site of the validation of the WHO Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) study.

His current research interests include: screening for problematic substance use and assessing the efficacy of brief interventions in different at risk groups; the clinical pharmacology and psychopharmacology of drugs of abuse; and clinical effectiveness of pharmacotherapies used to treat alcohol and drug problems.

Visit David’s university profile page


Khylee Quince is from the iwi of Te Roroa/Ngapuhi and Ngati Porou. She teaches criminal law, advanced criminal law and youth justice. Her research interests lie within those fields – in particular, Māori and the criminal justice system, tikanga Māori and the law, restorative justice and alternative dispute resolution, Māori women and the law, and indigenous peoples and the law.

Prior to joining the University of Auckland’s Law Faculty in 1998, Khylee practiced in criminal and family law for three years. Khylee is now Associate Head of School and Director of Maori and Pacific Advancement at the AUT School of Law. She is also a trustee on the New Zealand Drug Foundation.

Visit Khylee’s university profile page

University of Otago

Doug Sellman is a psychiatrist and addiction medicine specialist. He is recognised as a national leader in the addiction field in New Zealand having been Director of the National Addiction Centre (NAC), University of Otago Christchurch from 1996–2017. He has also contributed to the development of a highly successful national postgraduate training programme in the area of addiction and co-existing disorders. He has been involved in a broad range of addiction-related research projects with over 100 peer-reviewed publications involving alcohol, cannabis, opioids, nicotine, methamphetamine, gambling and food, primarily from a treatment perspective.

Over the past 15 years this work has turned increasingly towards public health and prevention. He was promoted to a Personal Chair within the University of Otago in 2006, and in 2009 was one of the initiators of Alcohol Action NZ, a medically-led advocacy group for alcohol law reform. His clinical work was in adult addiction services from 1987–1994 and then in youth services from 1994–2014. He is now partially retired and runs a small private practice with a special focus on food addiction and obesity, while continuing research and teaching work at the NAC.

Visit Doug’s university profile page

University of Auckland

Tamasailau Suaalii-Sauni currently teaches in the criminology programme. She completed both undergraduate and postgraduate university studies at the University of Auckland. She held teaching fellow, research fellow, lecturing and deputy director positions within the University of Auckland’s Department of Sociology, Department of Maori and Pacific Health, and Centre for Pacific Studies 1998–2008. She moved to the University of Otago to take up a senior research fellow position with the Centre for International Health based at the National University of Samoa in Apia Nov 2008–July 2011. After this, she took up senior lecturer and programme director positions with Victoria University of Wellington’s (VUW) Va’aomanu Pasifika Unit from 2011–2016. Tamasailau returned to the University of Auckland in October 2016 as Associate Professor in Sociology/Criminology at the School of Social Sciences. As well as working for the university sector, Tamasailau has also held honorary and part-time senior researcher and programme evaluator roles in the state and private sector – mainly with the Waitemata District Health Board’s Clinical Research and Resource Centre (2003–2008), and with (as co-director) Pacific Research and Development Services Ltd (1998-2003). Tamasailau was a member of the Superu and VUW central ethics committees.

Visit Tamasailau’s university profile page

Massey University

Chris Wilkins is the leader of the drug research team at SHORE & Whariki Research Centre, College of Health, Massey University. Chris has research expertise in drug trends, drug markets, public health, and drug policy. Over the past 20 years he has completed a range of studies of drug use in New Zealand with particular focus on methamphetamine, cannabis, legal highs, ecstasy and the non-medical use of pharmaceuticals. Chris Wilkins has published numerous journal articles on drug use, contributed to three books and regularly reviews manuscripts for Addiction, the International Journal of Drug Policy, Drug & Alcohol Review and Drug and Alcohol Dependence. Chris Wilkins has been an invited speaker at international meetings convened by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), and at the United States National Institute for Drug Abuse Community Epidemiology Working Group (CEWG). He regularly presents papers at the annual meetings of the International Society for the Study of Drug Policy (ISSDP).

Visit Chris’ university profile page

Cannabis press gallery

View our curated list of cannabis news in Aotearoa New Zealand, updated fortnightly.


Read reflections from co-chairs Juliet and Tracey as the cannabis project progresses.