Problems surrounding the implementation of a central pillar of government changes to the welfare system are to be examined by MPs.
Work and Pensions Secretary Iain Duncan Smith will be asked to explain why the new Universal Credit will not be paid to about 700,000 people until after a planned 2017 deadline.
Shadow work and pensions secretary Rachel Reeves said ministers had "been forced to admit that they have completely missed their targets and Universal Credit will not now be rolled out before the election".
"David Cameron and Iain Duncan Smith repeatedly promised to deliver their flagship policy, Universal Credit, on time and within budget," she said.
"That claim, and the credibility they staked on it, now lie in tatters."