The federal government's plan to legalize pot could land an 18-year-old in jail for sharing a joint with a slightly younger friend, according to an Ottawa criminal lawyer who submitted his concerns to a House of Commons committee.

"This bill doesn't distinguish between a criminal selling illicit marijuana to a high school kid, and an 18-year-old who passes a joint to their 17-year-old friend," said Michael Spratt, a partner at the law firm Abergel Goldstein and Partners.

"That person could face 14 years in jail."

On Monday, MPs began five days of hearings on the government's proposed legislation. They're expected to question dozens of witnesses, including medical and legal professionals, police officers and pot producers.

The Liberals plan to have legislation passed by July 2018.

Implementing that law will be a job for the provinces. The Ontario government announced plans Friday to create 150 stand-alone marijuana stores as well as an online ordering service for the drug.

Michael Spratt, a criminal defence lawyer in Ottawa, said the federal government's plan to legalize pot could lead to too many criminal charges for youth. (CBC)

'A very blunt tool'

The federal government is under pressure to keep pot out of the hands of minors. The Canadian Medical Association has been among those who warn the drug is dangerous to developing brains.

That's a reasonable goal, said Spratt, but he argued the government should not pursue it by criminalizing youth.

While the bill allows adults to possess as much as 30 grams of marijuana in public without risking criminal charges, for youth the limit is five grams.

Public education would be a better approach to curb pot use among youth, Spratt said.

The government's focus on criminalization based on amount is a flaw elsewhere in the bill as well, Spratt said. People could face charges for having one more plant than the specific number the bill allows, or for having plants that are even one centimetre taller than the limit set in law.

That's very different from the rules around alcohol, another legal drug, Spratt said.

"When we use the Criminal Code to enforce social norms or have control over public policy, it's a very blunt tool," Spratt said.

No plans for automatic pardons

A second source of concern for Spratt is the absence of a plan for those already convicted of pot offences.

"Tens of thousands of Canadians have criminal records for an offence that will soon be legal," he said. "And the tragic part is that we know that people with offences on their record, these marijuana offences, are disproportionately poor, marginalized and racialized."

Public Safety Minister Ralph Goodale said last spring the government was not planning a general amnesty for past pot convictions. On Monday an assistant deputy minister re-iterated that stance to MPs.

The government is likely fearful of being perceived as soft on crime, Spratt said, as well well as spooked by the resources required to go through past records.

Spratt previously fought to overturn changes to the pardon process, which doubled the waiting period for people to apply. Courts in Ontario and B.C. have found the changes unconstitutional, but Spratt said people outside those provinces don't benefit from those decisions.

"People who have criminal records are stigmatized," he said. "They find it harder to get employment, to cross borders, to fully engage in educational opportunities."