The Liberal government reached a tentative agreement with the NDP and the Bloc Québécois about the conditions under which Parliament could reconvene this week — but the Conservatives' rejection of that deal could lead to MPs returning to the Commons on Monday.

"One sitting each week is unacceptable, even if it is eventually supplemented by a virtual sitting for a handful of additional MPs," Conservative Leader Andrew Scheer said during a news conference on Sunday. "Physical distancing means staying two metres apart, not staying away from Parliament."

The Official Opposition's insistence on meeting in the House of Commons three times a week means negotiations between federal parties remain up in the air on the eve of April 20 — the date MPs were intended to reconvene when Parliament adjourned five weeks ago.

The Liberal Party told its staff Sunday that if no deal is reached between all four parties before late Monday morning, the party will attend the House sitting in reduced numbers and with minimal staff present.

That scenario would see the NDP and the Bloc each sending three MPs to the House. B.C. MP Paul Manly would attend on behalf of the Greens.

Scheer said the Conservatives are sending the same number of MPs as the last emergency sitting. The Liberals told CBC News they would do the same.

Scheer is scheduled to speak about Parliament's return at 10:15 a.m. ET on Monday.

Liberals strike deal with NDP, Bloc

Earlier Sunday, Liberal House Leader Pablo Rodriguez shared on Twitter details of the agreement struck with the NDP and the Bloc, which includes a combination of in-person and virtual sittings each week.

"Under the agreement, the House of Commons will hold one day of in-person meetings per week, with a small group of MPs in the chamber. As well, there will be additional virtual sessions with a small number of MPs from across the country," the statement reads.

Here’s an update on the ongoing negotiations to bring back Parliament in a responsible way.<br><br>Voici une mise à jour sur les négociations pour rappeler le Parlement de façon responsable. <a href="https://twitter.com/hashtag/cdnpoli?src=hash&ref_src=twsrc%5Etfw">#cdnpoli</a> <a href="https://twitter.com/hashtag/polcan?src=hash&ref_src=twsrc%5Etfw">#polcan</a> <a href="https://t.co/7ywbdQNRch">pic.twitter.com/7ywbdQNRch</a> —@pablorodriguez

Rodriguez said the proposal will give MPs the same amount of time to question ministers and the prime minister as they would normally have under regular parliamentary circumstances.

During his Sunday COVID-19 briefing earlier in the day, Prime Minister Justin Trudeau criticized the Conservatives for their repeated calls to convene in the Commons' chamber.

"I'm looking forward to taking questions from opposition parties, but it has to be done in a responsible way and right now, the Conservatives are not taking a responsible approach," Trudeau said.

Deal includes more virtual sittings than Liberals previously offered

Late Saturday, CBC News learned that the Trudeau government had offered to compress five days of question period into two days a week.

The arrangement would have involved virtual sittings every Tuesday, with MPs across the country taking part in the equivalent of two question periods. On Wednesdays, a smaller number of MPs and the prime minister would sit in the House of Commons and face the equivalent of three question periods.

In contrast, the tentative deal between the Liberals, NDP and Bloc starts with a proposal for a single in-person sitting beginning this Wednesday.

By next week, one session would be held virtually on Tuesday, followed by a sitting in the chamber on Wednesday.

The following week — and all subsequent weeks — would see MPs meeting virtually on Tuesdays and Thursdays and in-person on Wednesdays, for a total of three sessions per week.

The arrangement is similar to the NDP's initial recommendation, which called for the House to meet in-person once a week on top of two virtual sessions that would involve hearing from a larger contingent of MPs.

"I think the reality is the more we are meeting in person, the more that increases the risk. That's why the NDP proposal, I think, makes a lot of sense," said NDP House Leader Peter Julian.

Bringing all MPs back never on the table, Scheer says

Trudeau said during his morning remarks that convening all 338 MPs and their staff in the House of Commons would amount to an "irresponsible" move due to public health guidance urging Canadians to practise physical distancing.

Scheer fired back at the prime minister for suggesting that any parties were advocating for a full roster of MPs to return to the Commons on Monday.

"That is completely false, and it's disingenuous to try to put that forward before Canadians as if that was a real scenario," Scheer said.

Conservatives have proposed a reasonable plan to keep Parliament open.<br> <br>We're getting better results for Canadians.<br> <br> <a href="https://t.co/rsgecZgltf">https://t.co/rsgecZgltf</a> —@AndrewScheer

The outgoing leader also said that his proposal — which includes two hours per session to question ministers — is in line with the protocols legislators followed during the government's last two emergency sittings.

"Thirty-two MPs attended representing all parties," Scheer said. "This allowed us to follow public health advice and still carry out our duties."

While the Green Party of Canada does not hold recognized party status, former leader Elizabeth May said she supports sitting in the Commons only if there is a compelling reason to do so, such as passing legislation.

Andrew Scheer has failed to make a compelling case for in person sittings. Greens remain committed to following public health advice and operating a virtual parliament. <a href="https://twitter.com/hashtag/GPC?src=hash&ref_src=twsrc%5Etfw">#GPC</a> <a href="https://twitter.com/hashtag/cdnpoli?src=hash&ref_src=twsrc%5Etfw">#cdnpoli</a> <a href="https://twitter.com/hashtag/GPC?src=hash&ref_src=twsrc%5Etfw">#GPC</a> <a href="https://t.co/Rnjw4s6kpg">https://t.co/Rnjw4s6kpg</a> —@ElizabethMay

Commenting on Scheer's insistence that virtual sittings do not allow for proper parliamentary scrutiny and oversight, May said she believes remote platforms do just fine when it comes to holding politicians to account.

"We've already seen standing committees meet by Zoom," May said in an interview with CBC News. "I've seen [Conservative MP] Pierre Poilievre go at Bill Morneau.… It wasn't any different in quality than question period. His opportunities were exactly the same."