QUEBEC CITY - Opposition parties and moderate students banded together on the eve of a marathon legislature session, urging Premier Jean Charest to scuttle a special law aimed at stopping striking students.

The news conference included the leaders of the Parti Quebecois and Quebec Solitaire, left-leaning parties that have staunchly supported the strike.

They were joined by two moderate students groups and a third student association that opposes the strike.

All of them launched a final appeal for dialogue to end the three-month stalemate.

Leo Bureau-Blouin, president of the moderate FECQ student group, said the special law won't solve the impasse.

"Many of us are making a final call for dialogue," he said. "A special law shouldn't preclude a honourable exit from this crisis or a negotiated agreement."

PQ Leader Pauline Marois urged the premier to sit down with student representatives.

"What I ask is to rise above the fray and be the premier of all Quebecers," she said.

Charest planned to have members of the provincial legislature sit all night and into late Friday morning to pass a law aimed at guaranteeing access to 25 schools that have been blockaded by mask-wearing protesters.

He said he'll scuttle the bill if student associations reach a deal to ratchet down pressure tactics.

The tactics include sit-ins and blockades that have led to skirmishes and arrests at 24 institutions in the Montreal area.

A report says Quebec would impose fines of hundreds of dollars on students who block classmates from buildings.

Fines would reportedly run into the thousands of dollars for student associations encouraging civil unrest.

Former education minister Line Beauchamp quit on Monday, accusing students groups of refusing to budge on their demand that the government cancel a seven-year, $1,800 tuition hike. $1,625 over five years.

The special law would suspend the winter semester until August in an attempt to allow for a cooling-off period.

There were clear signs that anarchy had become entrenched in some young hearts, as police arrested more than 120 people following a rampage through the streets of downtown Montreal a few hours after Charest's announcement.

A march by more than 7,000 students ended in a riot as students and supporters smashed store windows and clashed with police. Police in riot gear moved in to disperse the crowds using tear gas.

Earlier on Wednesday, scores of students bullied their way into law classes at the Universite du Quebec a Montreal, scrawling graffiti on the walls of campus buildings and occupying classrooms.

Civilians and journalists were attacked in both protests.