A push by the Australian Greens to legalise cannabis appears up in smoke after the Turnbull government and federal opposition rejected the plan.

Greens leader Richard Di Natale has called for reforms to the existing prohibition, saying the country's approach to illicit drugs was an "unmitigated disaster".

"We can take this out of the hands of drug dealers and crime gangs," Senator Di Natale told reporters in Sydney on Tuesday.

But Health Minister Greg Hunt called on the party to withdraw its suggestion, arguing it risks the health of Australians.

"Marijuana is a gateway drug. The risk of graduating to ice or to heroin from extended marijuana use is real and documented," the minister told reporters in Melbourne.

Asked why the government wouldn't want the tax revenue, Mr Hunt said it didn't want to put the mental health of Australians at risk.

But Senator Di Natale argues governments around the world are realising that prohibition of cannabis causes more harm than it prevents.

"It's time Australia joined them," he said.

The minor party wants to redefine cannabis as a legal substance, with licences issued for its production and sale.

A national agency would be established to issue those licences and oversee regulations.

It would also act as the single wholesaler for cannabis - purchasing cannabis from producers and selling it in plain packaging to retail stores.

Up to six plants could be grown for personal use.

Former Australian Federal Police commissioner Mick Palmer backed the Greens' policy, slamming the so-called "war on drugs" as an abysmal failure.

But Labor has no plans to legalise recreational cannabis, with leader Bill Shorten saying the party wanted to focus on removing regulatory road blocks for medicinal use.

He said the Greens had rehashed an existing policy, which was the equivalent of "political click-bait".

"I'm sure as the Greens political party know, much of the responsibility for this issue lies at state and territory levels," Mr Shorten told reporters in Cairns.

Western Australia's state Labor government was the first to rule out decriminalising or legalising cannabis on Tuesday.

The Greens leader, a former drug and alcohol doctor, pointed to a recent poll showing 55 per cent of Australians believed cannabis should be regulated and taxed like alcohol or tobacco.

He expects the plan to raise hundreds of millions of dollars in revenue, helping fund treatment, education and other harm-reduction programs.

Liberal Democrat David Leyonhjelm said his party had long-held the position of legalising marijuana, criticising the 80,000 cannabis-related arrests each year as a waste of police resources.

Crossbench senator Derryn Hinch also backed the Greens' push, saying "you'd ban alcohol and cigarettes" too if the argument was that it's bad for you.

The Australian Drug Law Reform Foundation's Alex Wodak said banning cannabis had distracted police from following up more serious crimes and helped make some criminals rich.