OTTAWA - The government's House leader is warning opposition parties that the Conservatives won't tolerate indefinite obstruction of their Senate reform agenda, reviving the spectre of a possible snap election.

With debate set to start Friday on a bill establishing a process for electing senators, Peter Van Loan wouldn't say whether the Tories are prepared to make Senate reform a confidence matter, over which their minority government could be toppled.

But he stressed that it is one of Prime Minister Stephen Harper's top five priorities and that "it matters a great deal to us." And, while he insisted the government doesn't want an election anytime soon, he hinted that the government's patience with obstruction of its Senate and justice agendas may be running out.

"That's a very good question that we have to ask ourselves, at what point do we find resistance and delay of the government priorities is something that can't be tolerated any longer?" Van Loan said in an interview.

"We certainly want to see some progress."

The government introduced Bill C-43, the Senate election legislation, four months ago but has delayed starting debate on it until now. The bill appears headed for a rough ride, with no opposition party likely to support it.

Van Loan noted that a less contentious bill, imposing an eight-year limit on senators' terms, has been tied up for 11 months in the Liberal-dominated Senate.

"The precedent is not good but we're hoping this (Senate election bill) will go a little bit faster."

If the bill is "frustrated at every turn . . . then we will have to evaluate how to respond to that," he added.

Harper kick-started the debate Wednesday, announcing that he will appoint Senate reform champion Bert Brown, winner of an Alberta Senate election in 2004, to the upper house. The opposition parties' unenthusiastic reaction to the move underscored the obstacles Harper faces in winning approval for C-43.

Liberal Leader Stephane Dion is opposed to electing senators in the absence of other reforms to address inequities in provincial representation and a mechanism to break potential deadlocks between the Senate and House of Commons.

The separatist Bloc Quebecois is likely to echo the position of the Ontario and Quebec governments, which maintain that electing senators requires a constitutional amendment approved by the provinces.

And New Democrats have long favoured abolishing the upper house altogether.

However, Van Loan said he's hopeful that opposition MPs may ultimately succumb to public pressure and support the bill.

"Canadians want to see this happen. It doesn't matter what region you're talking about, this is what Canadians want to have happen," he said.

"I think we've seen in the past that when Canadians want something to happen. . . the political parties, when the issue becomes debated and discussed, listen to Canadians."

Van Loan also expressed frustration with opposition foot-dragging on the government's law and order agenda, noting that dangerous offenders legislation remains in limbo, as does a bill imposing mandatory minimum sentences for gun crimes.

"I don't see any evidence that our justice agenda has been embraced and made it through the House of Commons yet."

Van Loan's warning that the government won't tolerate continued obstruction of its priorities comes just as opposition MPs were letting down their guard about a possible spring election. His veiled threat that the government is prepared to pull the plug could be aimed at keeping opposition parties off-balance.