Rishi Sunak is expected to unveil a new Brexit deal within days after Tory MPs were ordered to attend Parliament on Monday.
It sets the stage for potential fireworks in the Commons as there is a risk of a major row in the divided Tory Party.
Ex-Prime Minister Boris Johnson on Thursday refused to say whether his successor Mr Sunak could count on his support.
The PM has ordered Tory MPs to be on a three-line whip on Monday - meaning they must be in Westminster.
Cabinet ministers have also been told to be on standby for the possibility of a rare weekend conference call to sign off any proposals, according to The Times.
A No10 source refused to comment on speculation as they stressed that talks are "still ongoing".
It comes as Mr Sunak battles to strike a new deal over the controversial issue of post-Brexit trading rules for Northern Ireland.
The Prime Minister and his team insisted they remain in "active discussions" with the EU over the Northern Ireland Protocol - a key part of Mr Johnson's Brexit deal.
A deal had been hoped for this week but the Prime Minister's deputy spokesman said on Friday that "intensive discussions" with the EU were ongoing.
Unusually, they declined to set out Mr Sunak's plans for the weekend, only saying that he was working in No 10 on Friday.
"I haven't seen the final details of his diary for the weekend," they said.
They added there "may be" further talks with Brussels on Friday.
Mr Sunak is also battling to convince the Democratic Unionist Party to support the plans. The party's backing is seen as critical by No10.
Speaking on Friday the Foreign Secretary James Cleverly suggests any deal over the Protocol would not be signed off with the DUP's backing.
Mr Cleverly told Times Radio: "The things they're concerned about, the things we're concerned about, are absolutely in alignment and we are focused on resolving all the issues that need resolving.
"Some of them are technical trade issues and very complicated and some of them are really simple but important principles, like Northern Ireland's place as an integral part of the United Kingdom.
"And that sense of sovereignty, the importance of a democratic voice.
"So when, hopefully, we get those issues resolved then I would hope that the DUP would recognise that we've addressed their concerns and until we have addressed those concerns we're not going to sign off on the deal."
But it is also not yet clear whether Mr Sunak will give MPs a vote on any new deal.
On Wednesday he told MPs that Parliament will get to "express its view" on any deal - but Downing Street has refused to guarantee a vote.
Keir Starmer told the Prime Minister earlier this week his party would vote for an agreement if he is forced to rely on Opposition support.
The Labour leader also warned Mr Sunak that eventually the "irreconcilables" on the Tory backbenchers would "come after him".
He added: "The basis of this deal has been agreed for weeks, but it’s the same old story.
“The country has to wait while he plucks up the courage to take on the malcontents, the reckless and the wreckers on his own benches."
