The latest poll shows that most voters do not want recreational cannabis to be legalised.
The result, from the 1 NEWS Colmar Brunton Poll, showed that 52 per cent opposed legalisation, while 39 per cent favoured legalisation; 8 per cent did not know and 1 per cent said they would not vote.
It contrasts to other recent polls that showed majority support for legalisation, including last month when 52 per cent of those surveyed said in a Horizon poll that they would vote to legalise, while 37 per cent said they would vote 'no'.
Officials are currently putting together a draft bill that will outline a proposed regulatory regime for legal cannabis, which will then be put to the public in a vote at the 2020 election.
According to the 1 NEWS Colmar Brunton poll, younger voters who supported the Green Party were more likely to favour legalisation.
Older National Party supporters were more likely to vote for the status quo.
The poll was conducted between June 4 and June 8, a month after the Government released details about next year's referendum.
There will be a simple Yes/No question at the referendum, asking voters to either favour the regulatory regime outlined in the draft bill or the status quo.
Details already released of what will be in the bill include:
• Allowing products to be bought only in a licensed premise from a licensed and registered retailer, and banning online or remote sales
• A ban on using cannabis publicly, allowing it only in a special licensed premise or on private property
• Controls on the potency of cannabis in available products
• A legal purchase age will be 20
• A ban on advertising of cannabis products, and requiring products to carry health information
• A state licensing regime to control the supply chain and the manufacture of all products, such as resins and edibles
• A ban on all imports of cannabis unless through a state-licensed wholesaler
Other details still being worked include the limit of potency, the rules of the licensing regime, the level of taxation and how much of that should fund health and addiction services, and whether cannabis-related convictions should disqualify a person from working in a legal market.
Finding the right balance will be critical, as too many restrictions, such as high prices or too high a purchase age, would be unlikely to weaken the black market.
Whether the vote will be binding has been questioned, as the Government could choose to ignore the referendum results, or change the bill after the vote.
The National Party has not committed to following through with the will of the people until at least after it can see the draft bill.
A 1 NEWS Colmar Brunton poll in October last year showed that 46 per cent of voters favoured legalisation, while 41 per cent did not.
The Budget this year put $13.4 million towards the costs of the referendum.