Mike Bradley wants the prime minister to consider clearing the criminal records of people charged with possession of marijuana once the drug becomes legal.

The Sarnia mayor penned an open letter to Justin Trudeau Monday stating that, as the mayor of a border city, possession charges are of "great concern."

"Those charges of simple possession can cause loss of employment and the inability to travel, particularly to the United States of America," he explained. "These are often people who have no other convictions and who have lived lives that have contributed to Canada."

Sarnia Mayor Mike Bradley is calling on the Prime Minister to consider clearing the criminal records of Canadians with simple marijuana possession charges once it becomes legal. (Facebook)

Canada's federal government has committed to legalizing marijuana by July 1, 2018.

Scarborough Southwest MP Bill Blair, the prime minister's point person on the marijuana file, said the government understands the concerns of border cities.

"We recognize the impact that a criminal conviction for simple possession of cannabis can have on a Canadian and we are looking at ways in which we can respond fairly to those concerns," he said.

Liberal MP Bill Blair answers a question during Question Period in the House of Commons on Parliament Hill in Ottawa, on Thursday, Feb.25, 2016. THE CANADIAN PRESS/Adrian Wyld (Adrian Wyld/Canadian Press)

Blair added the government's first order of business is to pass legislation to make marijuana legal, then it will consider past criminal records.

"We're exploring various ways in which those concerns can be addressed, but quite frankly, until the new system of cannabis control ... is put in place the current law stands and we urge all Canadians to continue to obey the rule of law," he said.