MONTREAL (CBC) - Politicians in Quebec are calling on their counterparts in Ottawa to save the long-gun registry as a private members bill calling for its abolition heads to a vote in the House of Commons Wednesday.

Members of the national assembly passed a unanimous motion urging the federal government to preserve the national firearms registry.

Quebec Public Security Minister Jacques Dupuis said he wrote his federal counterpart Peter Van Loan as well as representatives from the three opposition parties on Tuesday night asking them to oppose the bill.

Dupuis said the registry has become a crucial tool for police.

But the opposition Parti Québécois said it is losing patience in the federal government.

The party wants the province to set up its own gun registry and claw back money from Ottawa to pay for it.

PQ intergovernmental affairs critic Alexandre Cloutier said the effectiveness of the registry has been eroded by the Harper government.

He said most guns are no longer registered because of repeated moratoriums enacted by Ottawa.

But Dupuis said a Quebec-only registry would not be effective because guns can easily cross provincial boundaries.

On Tuesday, Montreal police Chief Yvan Delorme issued a rare political statement defending the registry.

Delorme said the registry helped prevent a potential crime following the Dawson College shooting in 2007.

He said police received a report that another individual had been making similar threats.

The registry alerted officers that this person actually owned several guns which officers seized, Delorme said.

The vote on the registry comes nearly one month ahead of the 20th anniversary of an event that helped to inspire the creation of the registry, Delorme said.

Dec. 6 will mark the 20th anniversary of the École Polytechnique rampage, in which gunman Marc Lépine stormed into the university with a rifle, killed 14 female students and wounded 27 other people.