MPs will decide later whether to endorse a report that found Boris Johnson deliberately misled Parliament over lockdown parties in No 10.
A year-long inquiry from the Commons privileges committee said the former prime minister committed repeated offences with his Partygate denials.
It recommends he should have been suspended from the Commons for 90 days if he had remained an MP.
Rishi Sunak is yet to confirm whether he will vote on its findings.
It will be a free vote for Tory MPs, meaning party managers – known as whips – will not instruct them what to do at the vote, which is expected to take place on Monday evening after a debate.
The report is expected to pass easily, but it is unclear whether a vote will be recorded, with Mr Johnson asking his allies not to vote against it.
It is likely that some Conservative MPs could abstain or not turn up to take part.