Ministers were accused of being in "absolute denial" over their flagship benefit scheme after Esther McVey hailed it for showcasing "British innovation".
The Work and Pensions Secretary gave a ministerial statement to the Commons to defend Universal Credit (UC) and read out positive stories and data as she addressed a critical report from the National Audit Office (NAO), which said it cost more to administer than the previous system - among other concerns.
SNP economy spokeswoman Kirsty Blackman warned UC is "pushing families into poverty and hardship" and expressed fears for her Aberdeen North constituents when they transfer to the system, which merges six benefits into one, later this year.
Labour's Debbie Abrahams, a former shadow work and pensions secretary, said she could not believe what she was hearing from Ms McVey and added: "They are in absolute denial, not just about this report."
Neil Coyle, Labour MP for Bermondsey and Old Southwark, asked Ms McVey to meet one of his constituents "made homeless" after not meeting the UC income and earnings criteria - an offer she accepted.
But Conservative former work and pensions secretary Iain Duncan Smith dismissed the NAO report as "shoddy" while Tory Philip Davies (Shipley) bemoaned opposition MPs for "huffing and puffing" but not offering solutions.
Speaking in the Commons, Ms McVey said UC was a "unique example of great British innovation" and hailed the system as a world leader.
She added the benefit was replacing a system which "trapped people in unemployment and disincentivised work", telling MPs: "We are building an agile, adaptable system fit for the 21st century.
"We want people to reach their potential regardless of their circumstances or background, and we will make changes when required in order to achieve this ambition."
For Labour, shadow work and pensions secretary Margaret Greenwood said Ms McVey should "reflect on her department being forced by legal challenges four times in the last year to review payments to disabled people".
Ms Greenwood added: "The Government must now listen to the NAO, it must stop the rollout of Universal Credit and fix the flaws before anymore people are pushed into poverty by a benefit that is meant to protect them from it.
"Universal Credit is having a devastating impact on many people and will reach eight-and-a-half million people by 2024/25. The Secretary of State must now wake up to the misery being caused by her policy."
Mr Duncan Smith said of the NAO report: "They failed to take account of a whole series of issues, not least which were the Treasury signed off figures about savings £8 billion recurring a year and more importantly the changes made last November/December have actually made a huge difference to people's lives.
"I would urge her to carry on and say to the Public Accounts Committee they really do need to ask the question, who really polices this policeman?"
For the SNP, Ms Blackman said of the rollout of UC in Aberdeen: "I expect a massive increase in the number of people coming through my door facing financial hardship.
"It is already the case that my office refers one person to a food bank every fortnight in Scotland's third city because of the actions of this Tory Government."
Copyright (c) Press Association Ltd. 2018, All Rights Reserved. Picture (c) Kirsty O'Connor / PA Wire.