Ottawa is buzzing over word that the Conservatives may once again try to bring the minority Liberal government down before the end of the month.

The showdown could happen at the end of this week, or early next week, when the government's top priority budget add-on bill, Bill C-48, comes to a final vote.

"I expect we're going to have every member in our caucus here whenever the vote is," B.C. Conservative MP John Reynolds told CTV News on Wednesday. "Whether it's tomorrow or next week ... we will have every member here, and this government deserves to be defeated."

Known as the "NDP budget", C-48 would add $4.6 billion in social spending to the government's original budget. The shaky minority Liberals agreed to the extra spending in exchange for the support of the New Democrats.

It's an agreement that the Conservatives and the Bloc Quebecois staunchly oppose.

But on CTV Newsnet's Countdown: with Mike Duffy, Reynolds said a deal was made with Liberal House Leader Tony Valeri.

In that deal, the Tories would support the budget bill in exchange for the Liberals holding off on the divisive Bill C-38 -- the same sex marriage legislation -- until MPs return in the fall to Ottawa from their summer recess.

Reynolds says the Liberals broke that promise when they announced this week they're willing to extend the sitting of Parliament into the summer in order to bring C-38 to a vote.

"We agreed to pass the second finance bill. We agreed to do it last Thursday, but the government reneged on the deal," Reynolds said on Countdown.

But would the Conservatives really try to bring the government down over this alleged bit of betrayal?

"They are not going gently into this good summer," says CTV's chief parliamentary correspondent, Craig Oliver. "We're back into brinkmanship again. It's unlikely, but it's not improbable, that the Liberal government could fall in the next vote," he says.

"This is a serious attack on the government and it will come very quickly and we should be ready for it when it comes."

Liberal Deputy House Leader Mauril Belanger, meanwhile, is denying that such a deal was even made. He says the Liberals have always wanted to bring the budget bills and C-38 to a vote before the end of the session.

"The Conservatives have essentially sought to delay the members of Parliament in making decisions. So tomorrow we'll have an opportunity to decide whether we want to extend the session so we could deal with both of these pieces of legislation before the end of the session."

MPs are set to vote soon on whether to extend this session of Parliament to push C-38 and C-48 through the Commons.

The vote is expected to pass, because it has the support of most Liberals, the NDP and likely the Bloc.

If it doesn't pass, Valeri has indicated that the Liberals are prepared to go to House Speaker Peter Milliken and ask him to recall the House.

NDP House Leader Libby Davies says her party is willing to stay in session for as long as it takes because both the budget bills and same sex marriage are "long overdue" for a decision.

"In most other workplaces, people know when they have important work that's not yet finished, they usually stay and work before they go home. And that's precisely what we're doing."