The Tory leader, Kemi Badenoch, has offered her party's support to pass the reforms, meaning the Prime Minister would rely on opposition votes against his own party's rebellion.
Critics within Labour and trade unions have warned that it would be shameful for the Prime Minister to rely on Tory votes to pass the benefit cuts.
Labour MPs rebelling against the bill are reportedly undeterred by threats of losing the whip or deselection, fearing deselection by their constituents more if they support the cuts.