Lord Mandelson admitted that unemployment levels were "unacceptable" today as figures were set to hit a 15-year high of around 2.5 million.
But the Business Secretary insisted that even more people would be out of work if the Tories had been in power during the recession.
Interviewed on BBC Radio 4's Today programme, the peer said: "One thing I and the Government know is that any such level of unemployment is unacceptable.
"The question is, what is the Government doing about it, and what would be the level of unemployment if the Government had not intervened in the economy in the way in which we have?"
Lord Mandelson - currently "minding the shop" in Downing Street while Gordon Brown takes a holiday - said £5 billion was being spent on getting people back into jobs, whereas the Conservatives wanted to cut state investment in the economy by a similar amount.
He also renewed his attack on shadow chancellor George Osborne, branding his claim that the Tories were now the "progressive" force in British politics "rank hypocrisy" and "laughable".
Lord Mandelson said: "We are now investing £5 billion on helping people into jobs and helping those who, through no fault of their own, are finding themselves unemployed.
"Incidentally, that is £5 billion, which is exactly the equivalent of the sum that the Conservatives say they would cut from public spending, take straight out of the economy as we try to get out of this recession."
Turning to Mr Osborne's comments yesterday, the Cabinet minister insisted that the Opposition's ideas for reforming public services would "drive" people to private education and private healthcare.
"When the Tories talk euphemistically about independent provision, they are talking about private provision for those who can afford it, and no safety net, no social justice for those who can," he said.
"That exposes the gross hypocrisy and audacity of George Osborne's claim that he was making yesterday to represent a party of progressives.
"I have never heard anything more laughable in my life."
Lord Mandelson said he was "concerned" about the impact of the recession on the less well-off.
But he went on: "Social mobility is not getting worse. It is not getting better as quickly as we originally wanted to see."Reuse content