The proposed reforms aim to save £5bn annually but critics warn they could push 250,000 people, including 50,000 children, into poverty.
MPs considering voting against the welfare reforms have reportedly been threatened with deselection or losing the party whip.
An amendment seeking to pause the reforms is expected to be supported by up to 100 MPs, indicating significant internal opposition.
While Work and Pensions Secretary Liz Kendall defends the cuts as necessary for welfare state survival, rebel MPs propose wealth taxes as an alternative.