Thousands of single parents have been left short of money because of problems with a multi-million pound computer system intended to speed up payments.
Thousands of parents are waiting for payments
Since the Child Support Agency system was introduced in April only one third of the 152,000 applications for child maintenance have been processed.
Liberal Democrat Steve Webb, who obtained the figures, said families were missing out as a result.
The government said performance "is improving", despite the problems.
According to Mr Webb only four per cent of claimants have received money since the system was introduced.
He said many parents would be feeling bitter as promised reforms had not been delivered and they were out of pocket as a result.
The Liberal Democrats' work and pensions spokesman said: "We are talking about families who have broken up, where we need to make sure that the children are being properly supported financially."
He said that despite the millions spent on the new computer system "lots of parents who are trying to bring up their children, trying to support them, are not getting the money they need".
The system was supplied by EDS at a cost of £450m, the Daily Telegraph reported.
The same company supplied the computer system for the government's tax credits, which were hit be a series of delays when they were launched earlier this year.
"The tax payer should not be handing over money until these things are made to work," Mr Webb said.
Despite government claims that the situation was improving, Mr Webb said the delay involved significant costs for the people affected.
He said some families would receive more money if they were successfully transferred to the new system and that the government should honour that commitment while the problems continued.
A spokesman for the Department for Work and Pensions told the Daily Telegraph that Mr Webb had misused statistics.
He said that of the 53,000 applications processed so far, around 40 per cent ended with the case being closed - meaning more than four per cent of applicants got their money.