OTTAWA — The Liberals are calling on the governing Conservatives to "come clean" about alleged links to a powerful American gun lobby group.

But the Tories deny any connection to the National Rifle Association and dismiss the claim as a "conspiracy theory."

Liberal House leader David McGuinty is turning up the heat in the debate over the long-gun registry, the subject of a cliff-hanger Commons vote next week.

But he offered little evidence Tuesday of any ties between the Tories and the NRA, which vehemently opposes gun control.

He cited news reports suggesting the NRA coached Canadian firearms groups on lobbying techniques. And he said that in 2006, Tory MP Garry Breitkreuz co-hosted a forum which featured the head of the NRA as a keynote speaker.

Prime Minister Stephen Harper dismissed Liberal accusations that the Tories are under the influence of U.S gun lobbyists.

"This friends, is typical of the arrogant intellectual contempt in which the Liberal party holds so many people, especially in rural Canada," Harper told a crowd of supporters in Edwards, Ont., Tuesday night.

He said farmers, hunters and even police officers understand the registry is wasteful and targets resources on the wrong people.

"It is never going to be accepted by the people in our society it is targeted at," Harper said.

"This government and this party is not going to rest until that long gun registry is abolished."

On Monday, CBC News reported that the NRA has been involved for more than a decade in efforts to kill the long-gun registry by providing support to anti-registry groups in Canada.

McGuinty said the U.S. gun lobby has no business being involved at all in a Canadian debate.

"We are here to say that the National Rifle Association and its members and its leadership should butt out of Canada's gun registry debate.

"This is a government that is choosing to listen to a powerful foreign influence over our own police, our victims' groups, our medical experts, in fact the majority of Canadians when it comes to gun control."

Conservative MP Pierre Poilievre, parliamentary secretary to the prime minister, said the Tories do work with firearms groups but they are domestic organizations.

"The Conservative party is working with uniquely Canadian organizations in order to scrap the wasteful, billion-dollar, long-gun registry."

The fate of a Tory private member's bill to kill the registry rests on a Commons vote next week. A House committee has recommended that the bill not proceed to third reading. If the recommendation is accepted, the bill is dead.

The numbers are extremely close. The bill passed second reading with the help of 12 New Democrats and eight Liberals. The Liberals say they will whip their caucus to vote against it this time.

The New Democrats allow MPs to vote as they will on private bills, but party leader Jack Layton said Tuesday that he has mustered enough votes to kill the bill and save the registry.