Former Greens MP hopes to legalise cannabis in NSW

"We know the war on cannabis has failed and that prohibition creates more harm than it aims to prevent," Mr Buckingham said on Monday.

The party maintains the criminalisation of cannabis use and possession are both ineffective and unfair, and have a disproportionate impact on sick, young and Indigenous people.

Also running on the party's ticket is former Australian Idol host James Mathison.

The party is confident after having two upper house MPs elected in the most recent Victorian and West Australian elections.

"We think there's a good chance (and) we're going to run a positive campaign," Mr Buckingham told AAP.

"The majority of Australians now support legalisation."

Medicinal cannabis use is growing across NSW, with close to 500,000 people using the drug nationally.

Mr Buckingham - previously an MLC for the NSW Greens - resigned from the party in 2018 after Greens MP Jenny Leong used parliamentary privilege to demand his resignation over a 2011 incident she described as "sexual violence".

Mr Buckingham, who denied any wrongdoing, criticised the Greens at the time, saying it had become a toxic organisation that had abandoned its core values.

His resignation came after months of infighting and pressure from his parliamentary colleagues.

Despite his controversial exit, Mr Buckingham said he was ready to return to the political fray.

"I've still got a lot of friends in the environmental movement," he said.

"I'll be happy to work with the Greens to get cannabis law reform over the line."

If elected, the party will push to make cannabis legal for adults and to change road rules the party says discriminate against users. It also wants criminal records for prior cannabis offences to be expunged.

"The criminalisation of cannabis and laws associated with it make this a health issue, an environmental issue, a justice issue. And for those who cannot use the medicine they need, a human rights issue," Mr Buckingham said.

Australian Associated Press