Cannabis for personal use, if supported in a referendum, would not become legal until around late 2021 under a proposal set to go to Cabinet on Monday.
The Herald understands the proposal will include drawing up a bill with details of a proposed regulatory regime for a legal market, but the bill would only have a first reading if there was majority support to legalise in the 2020 referendum.
That would make the referendum result non-binding, though it would be a brave new Government after the 2020 election that ignored a 'yes' vote, especially as the leaders of Labour and National have both said they would follow through with what the people wanted.
It normally takes about a year for a bill to pass through all its legislative stages, meaning a regime would not come into effect until towards the end of 2021 in the event of a 'yes' vote.
The referendum to legalise cannabis for personal use is part of the Labour-Greens confidence and supply agreement.
The Herald understands the option Cabinet will consider has been approved by the Green Party and the New Zealand First caucuses.
It will include some regulatory details including a legal age limit for purchase - likely to be at least 18 - strict limits on marketing and availability, a ban on consuming in public places, and allowing a "common sense" amount of cannabis to be home-grown.
The Herald understands there are plans for a public consultation process, and the proposed bill will aim to reduce drug-related harm, protect young people, and cripple the livelihood of gangs that benefit from the current prohibition model.
Not all details have been confirmed, and it is unclear if the paper to go before Cabinet will include proposed limits on THC potency or the types of products, such as edibles.
Using tax revenue from cannabis products to fund health services is also a possibility, although there are concerns that this would create a perverse incentive in a similar way that money from gambling is funnelled back into communities.
Drug Foundation executive director Ross Bell said he hoped there would be a decent period of public engagement, not simply informing people about the how to cast their vote in the referendum.
"We need to allow the public to have some input, an opportunity to get down and dirty in the detail and have a say," Bell said.
"Are we going to allow sales? If we do, is the purchase age going to be 18 or 20? What kind of products will be allowed?
"We would want to see very strict public health regulations, controls over marketing, potency, and an ability to tax the sales and use that income to fund drug treatment and prevention services."
Bell agreed with National Party drug reform spokeswoman Paula Bennett, who said there was still time to pass a bill into law and have its implementation dependent on the outcome of the 2020 vote.
"The legislation going through the House would give it the most scrutiny and be the most open and transparent process," Bennett said.
"How people vote, I'm fairly neutral on that. I just want people to know what we're voting for.
"We're on the edge of not having enough time, so I hope they act swiftly, the public get all the information, and they're putting money aside for an education campaign for all sides of the debate."
Justice Minister Andrew Little declined to comment other than to say that there would be an announcement shortly.
A poll in January showed that 60 per cent of New Zealanders would vote to legalise cannabis for personal use in a referendum, 24 per cent would vote 'no', and 16 per cent had no opinion.
Almost two in three people surveyed supported a regulated market with licensed operators, while 39 per cent thought that a legal purchase age of 18 would be best.