Dunedin North MP David Clark is intending to vote in favour of cannabis legalisation next year's referendum.
The Health Minister told TVNZ1's Q+A last night, "prohibition doesn't work".
The public is set to vote on whether cannabis should be legalised in a referendum alongside the 2020 general election.
"I will probably vote in favour of it," Dr Clark said. "This is a conscience issue, this is not as Minister of Health."
"My experience is prohibition doesn't work. Cannabis is currently prohibited and unfortunately people will get it who shouldn't."
"It's happened before with alcohol in the US.
"It's an issue where good quality regulation can make sure that it doesn't fall into the wrong hands."
The latest 1 NEWS Colmar Brunton Poll indicated 52 per cent of New Zealanders intended to vote against legalisation, 39 per cent wanted cannabis legalised, eight per cent did not know or refused to answer and 1 per cent said they would not vote.
Q+A is on TVNZ1 Mondays at 9.30pm, and the episode is then available on TVNZ OnDemand and as a podcast in all the usual places.