The Tories have demanded that the government accept the parliamentary ombudsman's ruling criticising its guidance on company pensions.
PAG members protest at Labour's 2004 Brighton conference
Shadow work and pensions secretary Philip Hammond said the ombudsman, Ann Abraham, should not be ignored.
The report says government leaflets gave a misleading impression of the security of company pension schemes.
But Work and Pensions Secretary John Hutton rejected her calls to compensate 85,000 people whose pensions suffered.
For the Lib Dems, David Laws accused Mr Hutton of "trampling over" the ombudsman's report.
Ms Abraham argued in her 254-page report that the government's "maladministration" had "caused injustice to a large number of people who, as a result, lost the opportunity to make informed choices about their future".
She said official guidance on company pension schemes had been "inaccurate, incomplete, unclear and inconsistent".
But the report is non-binding and the ombudsman cannot force the government to take up her recommendations.
And the government has refused to take the blame.
Mr Hutton said: "We do not believe the findings of maladministration can be supported by the facts.
"It simply cannot be right that the losses from schemes that have collapsed should be met by the taxpayer without establishing any causal connection between the actions criticised in the ombudsman's report and the losses that people have incurred."
But Mr Hammond accused Mr Hutton of acting as "judge and jury" in his own case
And he called his rejection of Ms Abraham's finding of maladministration "a direct challenge to the authority of Parliament".
Mr Hammond told MPs they "must insist that the government bows to the decision" of the ombudsman.
"The government must accept the ombudsman's factual findings of maladministration without delay.
"If they don't the authority of Parliament and the credibility of the ombudsman's office will be critically undermined."
The 85,000 people who lost all or part of their company pensions "are decent people who have sought to do the right thing and have seen their dreams of a comfortable and secure retirement cruelly shattered", Mr Hammond added.
And the government owed them an apology.
But Mr Hutton accused Mr Hammond of knowing nothing about the issue.
He said the Tories, when in power, had had plenty of opportunities to devise a compensation scheme, but had completely failed to do so.
"There will be many, many people in the country who will regard this as crocodile tears from you," Mr Hutton told Mr Hammond.
Mr Laws said: "If the government is going to trample over the reports of the ombudsman in this way, what is the point of having an ombudsman and giving her these responsibilities?"
"Your response to the ombudsman's report will have created a greater sense of anger and betrayal on the part of people who have lost their pensions," he told Mr Hutton.
"Isn't the excuse peppered throughout your statement that people should have read the small print more the approach of a dodgy second-hand car dealer?"
Mr Hutton hit back: "It is simply untrue to say the government is not seeking to provide financial support for people caught up in these circumstances.
"We are looking to see what more we can do."