The Child Support Agency reform was one of the "greatest public administration disasters of recent times," MPs say.
Parents and staff suffered during the CSA reforms, MPs say
The public accounts committee said the CSA had a catalogue of complaints, a backlog of cases, and poor enforcement of uncollected payments.
Chairman Edward Leigh urged the government to keep an "iron grip" on its replacement to make sure lessons had been learnt from the debacle.
The Child Maintenance and Enforcement Commission is due to be set up in 2008.
The CSA, established in 1993, has come under prolonged attack for not delivering, with the then Work and Pensions Secretary John Hutton finally announcing in 2006 that it would be scrapped.
Mr Hutton said this was necessary as the agency had a backlog of 300,000 cases and little prospect of recovering some £3bn in maintenance payments.
But Mr Leigh was doubtful about the future for child support payments under the commission.
"It is by no means clear how this will benefit citizens or regain the confidence of those the agency was intended to help."
He said the "disaster" of reform was evident for a variety of reasons, including the IT system.
"The agency threw huge sums of money at a new IT system which was intended to underpin the reforms.
"The Department for Work and Pensions never really knew what it was doing in dealing with the contractors EDS and the system was a turkey from day one."
He said about 500 defects remained three years after its introduction, and "staff confidence has been seriously damaged".
The public's reaction to the CSA was also a factor: "It is hard to think of a body in which the public has less confidence: in 2005-06 alone, there were 55,000 complaints about the CSA," Mr Leigh said.
He was speaking as the committee published its report into the reforms, based on evidence from the Child Support Agency and the Department for Work and Pensions.
The CSA collects regular payments from non-resident parents, but by October 2006 one in four applications for maintenance - received by the agency since 2003 - were still waiting to be cleared.
There was also a backlog of a quarter of a million cases waiting to be processed, and around 36,000 cases were "simply stuck in the system", the committee's report said.
It criticised the CSA for not making full use of forcing absent parents to pay, with about 60% of unpaid maintenance now considered unrecoverable.
"A significant consequence is that anyone considering not paying maintenance knows that they have a good chance of avoiding detection or serious penalty."
Peter Hain, who replaced Mr Hutton as work and pensions secretary in Gordon Brown's Cabinet last month, said the commission would "mark a clean break with the past".
It will have tougher powers to force absent parents to pay for their children, including taking money out of people's bank accounts if they fail to co-operate, imposing curfews and taking passports.
"We know that previous reforms have not worked. That is why we are replacing the CSA with a radically different child maintenance system," Mr Hain said.
"We have learnt lessons from the past. The new system will lift children out of poverty, give power and choice to parents, enforce responsibilities, and deliver value for taxpayers."
The commission is due to be established next year and start accepting applications in 2010.
Shadow minister for family welfare Maria Miller said the party wanted parents to take responsibility for their children but was worried about a lack of detail on how this would be achieved.
"The government needs to reassure the many thousands of children and families that are currently trapped in the Child Support Agency that the mistakes of the last 10 years will not be repeated, and that they will not be creating a CSA Mk III," she said.