A vote of no confidence in the current government could be held as soon as next week according to senior SNP MP Stewart Hosie.
Hosie said removing Prime Minister Boris Johnson from office may be the only way to guarantee the avoidance of a no-deal Brexit.
SNP leader Nicole Sturgeon also suggested on Friday she may back Jeremy Corbyn becoming a “caretaker” Prime Minister.
Hosie said opposition parties were discussing when to time a no-confidence vote with the aim to install a temporary leader to arrange a Brexit delay.
There are fears that Johnson could try to circumvent the “Benn Bill” requiring him to seek an extension if an agreement with the EU is not reached.
“We have to do that because there is now no confidence that the Prime Minister will obey the law and seek the extension that parliament voted for only a few weeks ago,” he told the BBC.
“If we are serious about the extension that is the only game in town.”
He also suggested a vote could take place as early as Monday or Tuesday, but acknowledged there would need to be agreement among opposing parties and Tory rebels.
The Liberal Democrats have already stated that Corbyn is too divisive a figure to play such a role.
Leader Jo Swinson said an “emergency government” may be required that not all parties could unite around Corbyn as the leader of it.
She said her party have suggested alternative MPs, including several senior members who plan to step down at the next election.
Hosie said: “If another name came forward that was acceptable to everybody, a Ken Clarke or Dominic Grieve-type figure, then self-evidently that would be a good thing to do.
“But it is also self-evidently the case that the second largest party (Labour) should have the first chance to form that administration.
“If Jo Swinson and the Lib Dems are actually serious about their stopping Brexit position then they need to stop playing political games, get on board with everybody else.”
A no-confidence vote would allow parliament to vote on whether they want the current government to continue.
If it loses the vote, MPs have 14 days to support an alternative but it must command a majority of support from the House of Commons, or a general election would likely be held.
Hosie said it was vital a plan was in place to ensure a Brexit extension and not allow a general election on “Johnson’s terms”.
“If that is not in place and effectively pre-agreed, then we might end up having the general election on Boris Johnson’s terms and allowing him to run down the clock and crash out without a deal,” he said.
Labour leader Corbyn also said he had a “productive meeting” with opposition parties on Thursday.
He said: “Our priority, all of us, is to prevent a no-deal exit from the European Union on the 31st.
“And to make the government carry out the EU number two act which requires them, in the event of a no-deal, to apply for an extension before the 31st of October so that we can continue our normal trading arrangements and then have a serious discussion about the future.
“At that point, we’re ready for an election. But the priority is to prevent a no-deal exit, with all the problems this could cause the people of this country.”