Fewer than half the forms sent to parents with care of the children were correctly completed, so only 344,000 maintenance inquiry forms were sent to absentees and just 170,700 assessments were made.
Ros Hepplewhite, chief executive of the agency, has a performance-related pay bonus tied to achieving the Government's targets - which include customer satisfaction. A spokeswoman for the CSA said it was 'premature' to ask whether Mrs Hepplewhite will receive her bonus on top of her pounds 46,000-a-year salary. The total savings that will eventually be counted as having been made in the first year will not be known until more assessments are completed.
Over the past 12 months, the CSA has been accused of failing to live up to its original purpose of forcing maintenance out of absent parents who were not contributing.
Instead, it appeared to target absent parents - fathers, nine times out of ten - who were already paying maintenance in order to increase payments, reduce the dependence on state benefits of the parent with care, and achieve greater savings for the Treasury.
However, the agency estimates that in about 50 per cent of cases in which forms have been sent out maintenance was not being received. And to the end of January, the CSA had tracked down more than 19,000 absentees for whom the other parent could not provide an address. The agency could not say how many of those who had completed assessments were not previously paying maintenance.
Last month, the Department of Social Security published figures showing that about 7,000 parents with care who were previously on income support had been able to get work as a result of increased maintenance payments to help with childcare costs.
And in a report last week the National Council for One Parents Families said that where the agency had been successful in securing increased maintenance payments it had 'transformed the lives of the beneficiaries'. However, the group complained that the CSA was failing to deliver for the majority of the 1 million lone parents on income support.
The most vocal opponents of the CSA have been absent fathers and second wives. One group, the Campaign for Fair Maintenance, has a national network of almost 200 local groups and claims to have been contacted by 100,000 people.
Critics claim the agency is causing financial hardship and upsetting delicately balanced access and maintenance arrangements. In extreme cases, fathers and second families have fled the country, and in at least five cases the CSA has been accused of driving fathers to suicide.
In December, the Government was forced to backtrack and introduce some modifications to the formula to phase in increased payments and leave absent parents with more cash.
But MPs and newspapers are still being inundated with letters from people claiming that the system is unfair and takes little account of ability to pay.
Grievances include: that the CSA takes no account of the cost of travelling to work when assessing how much a person can afford to pay; that previous 'clean-break settlements' under which the home or a capital settlement was given in lieu of maintenance are ignored in assessments; that the law includes couples who split up years ago; that maintenance is assessed from the moment an inquiry form is received so arrears build up even though the assessment may be disputed.