Theresa May will attempt to get MPs to back part of her Brexit deal later, in a bid to secure a delay until 22 May, BBC reports.
MPs will vote on the withdrawal agreement, which sets out the terms of the UK's departure from the EU.
Ministers say their backing is vital if Britain is to avoid a disorderly exit.
But Labour will vote against it, saying that denying MPs a say on the political declaration section of the deal, which outlines the shape of future UK-EU relations, is a "blindfold Brexit".
Friday's vote will not allow Parliament to ratify the entire withdrawal package, because the law allows this only after the passage of a "meaningful vote" on both parts of the deal.
The prime minister has already lost two such votes on the full deal by large margins, and Commons Speaker John Bercow had ruled out bringing the same motion back a third time without "substantial" changes.