The Drug Foundation says the time is right for New Zealand to consider legalising cannabis after three more US states voted for law reform.
Last month California, Massachusetts and Nevada approved recreational use.
In the state of California, marijuana is big business. It's been sold across the counter for the past 20 years.
Dispensary owner Carlos De La Torre says until now customers had to have a doctor's prescription.
"After 20 years, it's about time that we're finally doing the things that are going to be required to have a healthy and responsible cannabis industry in Southern California."
"It's an excellent source of medicine for those with colorectal cancers, prostate cancers," he says.
His Los Angeles medicinal marijuana dispensary has its own library of cannabis literature and employs scientists to research its effects.
And he'll be one of those best placed to profit when the marijuana market opens up to all adult customers.
"Yeah, of course it's a big opportunity, when you're talking about tripling or quadrupling the size of your patient base."
California's Proposition 64 was passed during last month's US election by a majority of Republicans and Democrats alike.
It makes cannabis possession legal for those over 21.
Stores will have to have a licence to sell it and taxes on those sales are projected to earn a billion dollars in the first year alone.
"It's going to create billions of dollars in revenue that the city can earmark for education, infrastructure, things that are important."
California is not the first state to legalise the drug, but with 40 million people, it's by far the largest.
And Armando Gudino, whose group Drug Policy Alliance helped write the law, say that points to bigger change.
"It's a big, big step towards ending, dismantling the war on drugs," Mr Gudino says.
The New Zealand Drug Foundation has conducted research that shows two-thirds of Kiwis support law reform.
"The public is ready for change; we're seeing that around the world and we're seeing it in New Zealand. Politicians aren't yet ready, but the public is," the Drug Foundation's Ross Bell says.
They say the US' free market model is not the only option for change.
A better choice may lie across the border, where Canada's planning big reform next year.
"They're going to reject a commercial model and in fact have government control, which is a more public health-focused approach - the kind I think New Zealand could learn from," Mr Bell says.
Until then, all eyes are on California as it builds the biggest marijuana market in the world.
Newshub.
