OTTAWA -- The Liberal government should follow the lead of American jurisdictions that have moved to erase criminal records for simple cannabis possession, says NDP justice critic Murray Rankin.

In late February, officials in San Francisco announced they would expunge more than 9,000 cannabis convictions dating back to 1975 -- a move that followed the passage of a bill last summer requiring California prosecutors to erase or reduce the severity of tens of thousands of convictions.

In Canada, the government has introduced a law making it much easier to apply for a pardon for a past conviction for cannabis possession, which would leave a record of that conviction accessible in certain circumstances. Another term for it is a "record suspension."

"In California, they're moving to expungement, not pardons," Rankin said in an interview. "The Democratic candidates for president are all talking about expungement. I wish (Canada's Liberals) would look south of the border to see that the debate they're having now has already happened and people understand that expungement is the way to go."

Expunging records means permanently destroying or removing them.

Canadian legislation -- known as the Expungement of Historically Unjust Convictions Act, which came into force in early 2018 -- allows for the destruction or permanent removal of judicial records of unjust convictions from federal databases.

Rankin, who is not seeking re-election this fall in his Victoria riding, said he will push to expunge the records of Canadians carrying simple cannabis possession convictions during his remaining time in Parliament because he sees a clear injustice that must be addressed.

The issue disproportionately affects black and Indigenous people, he said, adding the Trudeau government's current approach to suspend records rather than expunge them is far from enough to help an estimated 500,000 Canadians with past pot convictions.

The country has proven it is ready for cannabis legalization, he said, adding most Canadians would agree "the sky hasn't fallen" since pot was greenlit for personal use by adults.

"Let's finish the job for people who are marginalized and still bear a burden for something which is now completely legal," he said.

Rankin, who put forward his own private member's bill last year proposing the expungement of cannabis records, is urging the Liberal government to work with him to improve its own bill.

He said he's talked to Liberals and Conservatives who have taken "great interest" in expungement. Liberal MP Nathaniel Erskine-Smith has seconded Rankin's bill.

"If we can agree that expungement is the route to go, I would do everything I could with the opposition to assist them in getting a better bill for Canadians through Parliament," Rankin said.

A spokesperson for Public Safety Minister Ralph Goodale said Friday in a statement the government welcomes "constructive ideas" from any MP to improve the pardon bill and will consider proposals during the normal parliamentary process.

"Our government has accepted amendments from every party to other legislation tabled by Minister Goodale,"said Scott Bardsley, Goodale's manager of media and communications.

Goodale said when the bill was tabled that expungement is a "very new concept in the law" designed to deal exclusively with situations in which a previous law was a violation of human rights and would today be contrary to the charter.

"I would hope that they would work with me, allow me to work with them, in order to improve the bill," Rankin said. "If it's too late, I'm very sad and I'm very disturbed, actually, because they could have done this months ago and they should have ... Why he can't see that he should go all the way like the Americans are doing?"