Cannabis would be legalised and minor cannabis convictions wiped under a new report from The Helen Clark Foundation.

With New Zealand about to make a historic decision about whether to change the way we regulate the personal use of cannabis in 2020, the Foundation has analysed our current approach - and say the status quo is "unacceptable".

"Cannabis should be treated as a health and social issue, not a criminal one. The status quo is exacerbating its harm," says executive director, and report co-author, Kathy Errington.

Errington says the current prohibition-based policy approaches have not eradicated, and cannot eradicate, cannabis consumption and supply.

The Foundation notes that up to 80 percent of Kiwis will use cannabis at least once before they turn 25. Yet cannabis remains illegal, inflicting "excessive punishment" on those users who face prosecution.

Voters are therefore urged to tick 'yes' to cannabis legalisation and regulation in next year's referendum and the Government advised to regulate cannabis as a health and social issue.

"Our analysis argues that the disproportionately adverse effects of current policies justify putting in place legislation and effective regulation," Errington says.

The report recommends that the New Zealand Government should:

• Expunge prior minor cannabis offences from the record, including for supply where there are no compounding factors such as firearm use or violence
• Legislate for the regulation of a legal cannabis market.
• Develop a structure for a legal market which prevents and/or discourages large, commercial, for-profit cannabis producers and retailers
• Ensure those most affected by prohibition on cannabis use are considered when implementing a legal market
• Ensure these people have equitable access to become producers and retailers within the legal market

What New Zealand will vote on:

The draft legislation the Government announced New Zealand will vote on at the 2020 election will include:

• A minimum age of 20 to use and purchase recreational cannabis
• Regulations and commercial supply controls
• Limited home-growing options
• A public education programme
• Stakeholder engagement
• "There will be a clear choice for New Zealanders in a referendum at the 2020 General Election. Cabinet has agreed there will be a simple Yes/No question on the basis of a draft piece of legislation," Justice Minister Andrew Little said in May.

The Cabinet paper outlining details of the referendum highlights how legislation will include "licensed premises" which could "provide an opportunity for staff to monitor and promote safe consumption" of cannabis.

It says full regulation would limit cannabis consumption to private homes and licensed premises, and the drug could not be purchased online or by remote sale.

The Cabinet paper also acknowledged that should cannabis be legalised, the "model must promote equity and improve opportunities for Māori", as Māori are "more likely to receive a cannabis-related conviction than non-Māori".