There is majority support in Tasmania for the decriminalisation of recreational marijuana, according to a poll released by the Greens' candidate for the Braddon by-election Jarrod Edwards.

An Essential telephone poll of more than 1,100 Tasmanians found 59 per cent supported the move while 28 per cent opposed it.

The highest support was in Denison where 63 per cent were in favour and 23 per cent opposed.

The statewide figure was the same in Braddon (59 per cent) where the Greens candidate for the federal by-election, Jarrod Edwards, said it was a big issue.

"We want to decriminalise it because we feel that it takes up a tremendous amount of resources, not only in the court system but through social systems as well," he said.

"One in three Australian adults admit to trying or using marijuana, so its a widely used drug in the community.

"It greatly impedes and impacts on young people in our community if, during their formative years, they get drug charges on their record.

"It greatly inhibits their ability to gain employment, travel to some countries overseas and then it impacts their ability to purchase houses."

'Tough-on-drugs policy does enormous harm'

In April, Greens leader Richard Di Natale, who will be visiting Braddon today, declared his party wished to legalise cannabis for people over 18.

At the time, Senator Di Natale argued his party's proposal would not result in the widespread sale and use of cannabis, and claimed there would be strict regulations on sale and production.

The plan involved creating an agency to be the sole wholesaler of cannabis, as well as the outlet responsible for issuing licenses for prospective growers and retailers.

"Prohibition has failed. Using cannabis remains illegal, but this has not stopped Australians from using it," Di Natale said at the time.

"As a drug and alcohol doctor, I've seen that the 'tough on drugs' approach causes enormous harm.

"It drives people away from getting help when they need it and exposes them to a dangerous black market."

The policy has support from former Australian Federal Police (AFP) commissioner Mick Palmer.

But the Australian Medical Association did not support the idea, arguing there were serious physical and mental impacts of cannabis use.

In South Australia, cannabis possession has been decriminalised since 1987, with people carrying a small amount only facing fines.

But the SA Government now wants to quadruple the maximum fine for possessing cannabis to $2,000 and introduce a maximum two-year jail sentence.

The drug law review was a Liberal election promise for the March poll that installed Steven Marshall as Premier.

Last month, Canada became the second country after Uruguay to legalise recreational cannabis use.