George Osborne has come under fire for his absence in the House of Commons amid a row over planned cuts to disability benefits.
The chancellor sidestepped an emergency question posed by Labour's shadow chancellor John McDonnell, leaving David Gauke, the financial secretary to the Treasury, to respond for the government.
That prompted censure from a number of MPs, including opposition leader Jeremy Corbyn who noted that "practically every other cabinet minister is here today".
Labour's Yvette Cooper commented: "If the chancellor is too scared to answer questions in this house on the issue he is not fit to do the job."
Liberal Democrat leader Tim Farron lamented "the failure of the chancellor to be here to answer for himself".
Mr McDonnell, meanwhile, expressed sympathy for Mr Gauke who he said had been left by the chancellor to "defend the indefensible".
David Cameron responded to the debate saying the Chancellor would be in parliament on Tuesday to speak on the budget debate.
The row has blown up following the surprise resignation of former work and pensions secretary Iain Duncan Smith, who stepped down claiming the budget was "deeply unfair" and cut taxes for the better off while targeting those most in need.
After a weekend of acrimonious debate over Mr Duncan Smith's resignation, Mr Cameron said on Monday the former work and pensions secretary had "contributed an enormous amount" to government welfare reforms and could be "proud of what he achieved".
The prime minister also tried to reclaim some of his image as a social reformer, damaged by Mr Duncan Smiths resignation.
He said the Conservatives remained a "modern, compassionate" party, and highlighting plans for prison reform and the national living wage.