Work and Pensions Secretary Iain Duncan Smith has denied claims that his welfare reform programme is a "debacle".
Government attempts to set up Universal Credit scheme have already wasted £34 million according to a damning National Audit Office report.
Coalition ministers have traded blows over pensioners' benefits after Iain Duncan Smith urged the wealthy to hand the money back.
The Department for Work and Pensions has confirmed that £40.1 million had been written off on software and computing costs during the introduction of the new Universal Credit system.
Annual accounts will show £40.1m write-off for Universal Credit IT which includes the £34m we previously announced
Re discussion of £90m IT today - we will be using this while we continue to roll out UC over the next five years. Not a write-off.
The Work and Pensions Secretary Iain Duncan Smith has denied claims that his welfare reform programme is a "debacle".
Speaking in front of MPs today, Mr Duncan Smith admitted the introduction of the new system was running late, but revealed the IT problems that initially disrupted the programme were now fixed.
Work and Pensions Secretary Iain Duncan Smith has insisted his flagship welfare reforms remain on track, despite further delays to the programme.
Mr Duncan Smith disclosed last week that his 2017 target for the full introduction of Universal Credit is set to be missed - with around 700,000 claimants facing a longer wait.
Speaking ahead of his appearance before the Commons Work and Pensions Committee, he said the delay was to allow the most vulnerable claimants more time to adjust to the change.
"We could easily have tried to rush those people in but we have decided not to. I think it is only fair to give them longer," he told BBC Radio 4's Today programme.
"I do accept, of course, that this plan is different from the original plan."
Giving evidence alongside Iain Duncan Smith at the work and pensions select committee will be Howard Shiplee, the former London Olympics executive drafted in earlier this year to "reset" the Universal Credit programme amid growing concerns over delays and IT issues.
The Secretary of State may also be questioned about reports - which he denies - that he sought to have MPs pin blame for the failures on the DWP's chief civil servant Robert Devereux.
In his reply to the Autumn Statement, shadow chancellor Ed Balls taunted Mr Duncan Smith, commonly known as "IDS", over the reforms, suggesting it stood instead for "In Deep Shambles".
In written evidence to the committee, the DWP said it was "confident that it has taken, and continues to take, the right remedial steps to address past issues in the Universal Credit programme."
Shadow work and pensions secretary Rachel Reeves said the extent of the delay to the Government's introduction of Universal Credit was set out in data released by the Office for Budget Responsibility (OBR) alongside the Chancellor's Autumn Statement.
David Cameron and Iain Duncan Smith repeatedly promised to deliver their flagship policy 'on time and within budget'. That claim, and the credibility they staked on it, now lie in tatters.
– Shadow work and pensions secretary Rachel Reeves
For months on end the Government have tried to avoid answering questions about Universal Credit but these OBR figures tell the truth of how (they) have broken their promises on a spectacular scale.
They have 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 are presiding over a complete mess and it is taxpayers who are picking up the bill with at least one hundred million pounds of their money written off.
Iain Duncan Smith is to be grilled by MPs over the scale of delays to the Government's flagship welfare reform - Universal Credit.
The Work and Pensions Secretary - who will appear before the Commons committee today - has admitted the 2017 target for the full introduction of Universal Credit is set to be missed - with around 700,000 claimants facing a longer wait.
But Labour said official figures showed that only a tiny fraction of the numbers due to be using the new system by the time of the next general election would be transferred on time.
Only a "handful" of the promised 1.7 million would be switched by 2014/15 and only 400,000 by the following year - less than 10% of the original target, the Opposition said.
Work Secretary Iain Duncan Smith claimed a victory in the Supreme Court today despite it ruling that the 'back-to-work' schemes are legally flawed. He said:
– Iain Duncan Smith, Secretary of State for Work and Pensions
We are very pleased that the Supreme Court today unanimously upheld our right to require those claiming jobseeker's allowance to take part in programmes which will help get them into work.
We have always said that it was ridiculous to say that our schemes amounted to forced labour, and yet again we have won this argument.
Ultimately this judgment confirms that it is right that we expect people to take getting into work seriously if they want to claim benefits.
Moving three million people onto a new type of disability benefit, the Personal Independence Payment, was always going to be a complex matter.
And so it has proved - too complex in fact, because the Government has decided to delay the national roll-out of the scheme.
Ministers insist that this isn't a sign of chaos - that they haven't lost control of events - but that's exactly what Labour is accusing them of.
The problem for Iain Duncan Smith, the Work and Pensions Secretary, is that this is not the first of his flagship reforms to get into trouble.
Iain Duncan Smith has taken a swipe at his former Tory rival John Major today over the former prime minister's traffic cones hotline initiative during the 1990s.
The Secretary of State for Work and Pensions hit back after Major this week questioned his former colleague's ability to reform benefits.
Duncan Smith told the Evening Standard: “Well, as I say, I never really get too fussed about what people think about their own intellects. I’m always happy to be in awe of someone whose own intellect delivered us the cones hotline, I must say.”
Major's infamous telephone hotline was set up for people to call to complain about unattended roadworks and has gone down in political history as one of the most ridiculous initiatives launched by the British Government.