This has resulted in a delay in the launch of a new system for assessing child support payments by absent parents.
Work and pensions secretary Alistair Darling told the House of Commons that the planned start date of the end of April - which had already slipped by six months - was now not feasible.
He said when the agency was introduced in 1993 the implementation of the off-the-shelf 1970s system from Florida was rushed and the equipment not properly tested. The system descended into chaos within weeks.
Darling told MPs last week he was not prepared to repeat that mistake, "Fundamental to the delivery of our reforms to the Child Support Agency is getting the IT right. Tests are continuing, but they are not complete. We will proceed only when I am satisfied that it is working to the standards that we expect.
"I have, therefore, decided to defer the planned start date. The new system will be implemented only when the supporting IT is operating effectively,'' he said.
Darling refused to give a new target date to implement the computer system or give more details of what elements of the testing process were running behind.
The minister said EDS had already committed extra staff and resources to speeding up and completing the testing process.