The lawyer for the son of Maurice "Mom" Boucher, a convicted criminal who escaped a Montreal prison this week, is urging his client to return to custody before something bad happens.

Francis Boucher walked out of Bordeaux Prison on Monday, reportedly by posing as an inmate with a similar name who was due to be released.

Boucher, 39, was serving 117 days in jail for uttering death threats against police officers and was only due to be granted freedom at the end of May.

Now his lawyer, Dimitrios Strapatsas, is urging Boucher to come to his office, or to a police station, before he gets into trouble.

"The message to my client is to turn himself in as quickly as possible and to surrender himself to authorities at a police station or via a lawyer, I myself or a colleague of mine, as quickly as possible," said Strapatsas.

"So far things have not escalated, but there is a tactical team from the Surete du Quebec that's actively looking for Mr. Francis Boucher, and every police officer I'm sure is actively waiting or looking to see if they can find him."

The officer who let Boucher out of prison has been suspended with pay pending an investigation into what authorities are considering an escape.

There have been more than 180 jailbreaks from Quebec correctional facilities over the past eight years.

Boucher has a previous 10-year conviction for gangsterism, conspiracy to commit murder and drug trafficking following a major roundup in 2001.

He stands 5'9" (1.8 m) weighs 165 lbs (75 kg), has green eyes and salt-and-pepper hair.

Anybody who spots him is asked to call 911.