MPs studying a bill that would make it illegal for rioters to cover their faces have doubled the proposed penalty to 10 years.

Conservative MPs on the House justice committee changed the proposed law Thursday, sending the legislation back to the House of Commons with a maximum penalty of 10 years in jail rather than five.

The committee was studying Bill C-309, a proposed law that would make it a crime for people rioting or at an unlawful protest to conceal their identities.

Robert Goguen, parliamentary secretary to the justice minister, put forward the change.

The bill should be back in the House of Commons next week for a final vote before going to the Senate.

Blake Richards, the Conservative backbencher who proposed the new legislation, says he was open to the change because it harmonized with a section in the Criminal Code that already criminalizes the wearing of a disguise.

"The idea is they’re trying to harmonize it with Section 351 of the Criminal Code which deals with similar types of offences, so obviously it makes a lot of sense," he said.

Giving police new tool

Section 351 already makes it illegal for anyone to wear a disguise to commit an indictable offence, which one expert told the committee made Richards's bill unnecessary.

Richards said he had heard from police that it was almost impossible to use that offence to charge rioters, because it was intended to be used in cases of armed robbery. He wrote C-309 to give police another tool to prosecute rioters, he said.

"The idea here is that this applies to individuals who are participating in an unlawful assembly or in a riot, so the separate offence of the mask is an aggravating factor, of course, to participating in that kind of event."

Participating in a riot is an indictable offence that would be covered under the existing provision. But taking part in an unlawful assembly is a less serious crime, which wouldn't be covered by the existing law. An unlawful assembly is a gathering that causes fear.

It's up to city officials to decide what constitutes a riot.

NDP MP Françoise Boivin wanted the committee to change the language in the bill so the wording matched the existing measure.

The current law is phrased as wearing a disguise "with intent to commit" an offence, but Richards's bill simply says "commits an offence."

Lawyers will 'have a field day'

Boivin, a lawyer, said defence lawyers will "have a field day with it."

"Definitely it’s going to be contested," Boivin said.

Richards said Boivin's change would have made the bill "useless."

"That’s why it’s difficult for police to apply," he said.

The problem for police isn't in finding a crime with which to charge violent or destructive rioters, she added. It's about identifying those who commit the crimes if their faces are masked. Boivin said she fears police will see the bill as a way to pre-emptively arrest masked protesters, even if they're peaceful.

"Nothing in this bill is going to change that fact," she said. "It would seem they would arrest at random … you have a mask and we'll sort it out at the police station, but that's not how it's supposed to be."

"Let’s not oversimplify. I don’t want to protect those thugs or those criminals. I just don’t want to arrest innocent people."