The province launched a multi-pronged argument that the federal government is overstepping its bounds and is compromising Quebecers' safety by destroying the data.
Lawyers for the province told Justice Marc-Andre Blanchard that the data destruction goes against the federal-provincial balance of powers.
The federal law to destroy the registry came into effect in April everywhere else in Canada but, in Quebec, the long-gun registry has continued to function under court order.
Quebec said Monday in Superior Court that it was not trying to keep the federal registry alive, but wanted the data for its own registry, still in the works.
"By proceeding with the destruction, we certainly can't build (our own) the way we want it," said Quebec government lawyer Eric Dufour.
Their attack is on one specific section of the gun-registry law which calls on provincial firearms commissioners to destroy data as soon as possible.
Part of the federal law, in additional to eliminating the registry, also decriminalizes owning an unregistered long-gun.
"We don't see a rational or functional link between the destruction of the data and decriminalization," Dufour said, emphasizing that the registry was the creation of a partnership with Ottawa.
A federal lawyer will present Ottawa's arguments later this week.
Quebec lawyers have already succeeded twice in ensuring that the registry continues to function through court injunctions. That has meant long-guns continue to be registered in this province, a process that has ended elsewhere in Canada.
The last safeguard order signed by a Quebec judge in April, preserving the registry, is set to expire this week but the case isn't likely to end soon. This week's hearing is just one step in a case likely to end up before the Supreme Court of Canada.
The Harper government is opposed to relinquishing control of any part of the registry, which it is determined to destroy. It says Quebec can start from scratch if it wants to build a registry of its own.
Dufour argued Monday that not having the registry data could jeopardize Quebecers' safety.
For example, Dufour said, without the data, the Crown cannot know all the weapons that are in the possession of an individual facing a ban.
He also said that police will have less information available about a potential suspect they are trying to arrest and won't be as easily able to confiscate weapons from potentially dangerous people without complete information.
The bill to end the federal long-gun registry, C-19, received royal assent on April 5, fulfilling a longstanding promise by the Harper government.
Quebec is the only jurisdiction that has sought to keep information from the registry. The movement to create the gun-control measure was inspired by the Montreal massacre in 1989.
Heidi Rathjen, a witness to that tragedy and a gun-control advocate, says the data is essential for a registry and a registry is essential for proper gun control.
"The registry in Quebec has allowed the police to confiscate 2,500 guns in one year through prohibition orders," Rathjen said.
"Who knows what would have happened if these guns hadn't been removed?"Suggest a correction