Drug researchers are urging the Government to weigh up the potential health risks of cannabis reform.
While Prime Minister John Key's opposed to change, the latest public opinion poll shows a majority of people want it.
But Massey University drug policy expert Chris Wilkins says any change needs to be carefully thought out.
"The main point is a lot of things like alcohol and tobacco have known serious health risks, but that doesn't mean we prohibit them. Occasional use of cannabis has probably really modest health risks."
Dr Wilkins says strict regulatory and education policies would promote healthy use of the drug.
"We shouldn't treat cannabis like we do any other commodity in the supermarket - we've got to be a bit more careful about how we give people access to it and who should be using it."
He says calls for reform are only going to get stronger.
Mr Key said on Monday that decriminalisation would send the wrong message to youth.
"My personal view - it's my long-held view and I don't think I should necessarily change it - has very much been, 'What is the message that Parliament would ultimately be sending those youngsters?'
"We'd be telling the young people of New Zealand that it's okay - and I just don't know if we want to."