While most National Party supporters (53.8 per cent) favoured the status quo, almost 45 per cent supported legalisation or decriminalisation.
The Government last night remained firm in its stance on cannabis.
"We do not think there are any benefits for decriminalising or legalising cannabis, for medicinal purposes or otherwise, which outweigh the harm it causes to society," said Justice Minister Judith Collins.
Associate Health Minister Peter Dunne said there was no sense of any great political appetite for reform.
"If anything, what the debate on psychoactive substances did among the body politic was reinforce a more conservative attitude."
Cannabis is an illegal substance and possession carries a penalty of a $500 fine or three months' jail or both, though police exercise discretion.
Labour drug and alcohol spokesman Iain Lees-Galloway said there was a growing mood for reform.
"We wouldn't look at legalisation in the first instance, but we want to use the Law Commission report as a starting point for a conversation."
The commission's report, released three years ago, backed a three strikes mandatory cautioning regime with an emphasis on treatment, and advice on legal and health services. A fourth incident would result in prosecution.
The Green Party calls for no penalties for possession and use of cannabis for people aged 18 and over, though it still wants selling cannabis and cultivating for sale to be against the law.
Greens drug and alcohol spokesman Kevin Hague said the poll results reflected the fact that most people had smoked cannabis.
"And for most New Zealanders, it is evident that the current law isn't working. It's causing harm rather than solving it."
New Zealand First favours a citizens-initiated referendum, while the Act party would opt for a conscience vote if the issue came up in Parliament.
An Internet Party spokesman said while there was no official policy yet, strong feedback to the party favoured decriminalisation - a position that leader Laila Harre personally supported.
Mr Bell said New Zealanders have some of the highest cannabis-use rates in the world.
"We have troubling rates of youth cannabis use, and there are problems associated with that, in terms of mental and physical health.
"But we delude ourselves if we think the current criminal justice model is doing anything about this."
The poll was conducted from June 6 to 15, with a sample size of 750 and a margin of error of 3.6 per cent.
