Protesting students smashed storefronts in Montreal and confronted police after Quebec authorities announced an emergency law to suspend classes in a bid to restore order after months of protests over tuition hikes.

Several thousand students took to the streets late Wednesday to denounce the law announced by Quebec Premier Jean Charest, with some marchers targeting shop windows at major downtown banks and throwing projectiles at police. No arrests were made.

"It's time for calm to be restored," Charest, flanked by newly appointed Education Minister Michelle Courchesne, told reporters earlier Wednesday, with protests continuing into a 14th week amid a deadlock in negotiations.

"The current situation has lasted too long," said Charest in previewing legislation to suspend classes until August, pushing back the school year for 25 universities and colleges affected by the strikes, but not stepping back from the tuition fee increases at the heart of the student boycott.

Charest said the aim was to secure education for students at the boycotting institutions.

"No student will be forced... to return to class," he said, adding the bill aimed to ensure "those wishing to continue their education can do so in a safe and peaceful environment."

The demonstrations culminated Monday with the resignation of Quebec's education minister and rising political star, Line Beauchamp, following a standoff when students rejected a tentative deal last week to stretch tuition hike over seven years instead of five.

Beauchamp faced a stiff challenge from the more than 165,000 students striking over plans to raise school fees by 82 percent or $1,625 as part of an effort to rein in the budget deficit.

Police have started cracking down on the protests across the province, including in Montreal where 19 were arrested on Tuesday for blocking a main bridge to the island city.