Montreal city councillors have approved a bylaw that bans the wearing of masks at public protests.

The vote at Montreal City Hall on Friday afternoon passed 33-25.

"When a cause is just, why is it necessary to hide behind a mask?" Mayor Gérald Tremblay said during a news conference following the vote.

A woman protests against the proposed bylaw outside of Montreal City Hall Friday. (Shaun Malley/CBC) The bylaw will also force demonstrators to provide police with an itinerary for protests.

The bylaw will come into effect Saturday, Tremblay confirmed.

Opposition parties spent much of the morning pressing police Chief Marc Parent with their concerns that the bylaw would give police too much power to inhibit free speech.

There's also some debate over what constitutes a mask.

The leader of one of the city's opposition parties, Louise Harel, asked for clarification on whether scarves or bandanas worn by protesters protecting themselves against chemical irritants or tear gas would be included in the ban.

A lawyer for the police insisted those scarves are considered masks under the bylaw. The reasoning is, according to the lawyer, that if tear gas is being deployed, the demonstration has already been declared illegal.

Quebec City drops mask ban idea

Unlike Montreal, Quebec City will not move to ban masks during protests.

That provision had been included in a bylaw to be presented to council next week, but Mayor Régis Labeaume took it out.

City officials say their proposed rules are designed to prevent the Occupy-style protests that broke out last year.

P.O.V. Was Montreal right to ban masks during public protests? Have your say.

They will prevent people from camping overnight in municipal parks, cooking and other activities.

On the federal level, MPs are currently considering a law to ban masks at riots. The bill is awaiting its final two votes in the House of Commons and will then proceed to the Senate.

The private member's bill, sponsored by Conservative MP Blake Richards, would impose a 10-year penalty on rioters who try to conceal their identities.

The proposed law wouldn't apply to peaceful protests.