The total uncollected arrears accumulated over the entire 17-year lifetime of the Child Support Agency stands at over £3.78 billion, according to newly released figures.
More than £1.14bn in maintenance was collected or arranged in 2010, up from £1.13bn in the previous year.
The figures also reveal that nearly 700 properties owned by parents with child maintenance debts have been targeted for possible possession and sale to pay off their arrears. So far, orders for the sale of 100 properties have been granted though only a handful have had to be seized.
The agency has deployed new enforcement powers and increased its use of existing legal processes in order to recover child maintenance payments. The new powers include Deduction Orders, where money is forcibly removed from bank accounts.
The Child Maintenance Commissioner Stephen Geraghty said: "The number of children benefiting from maintenance payments has increased by more than 50% since 2005 when performance began to improve. We are putting more and more of our efforts into re-establishing compliance when payments are missed and making increasing use of our wide range of enforcement powers."
More than 600 lump sum and regular payment orders have been imposed, so far raising in excess of £1 million, the agency said. It is also pursuing the estates of more than 600 deceased parents so their children will benefit from their legacies.
In July 2010 a father who owed over £78,000 in unpaid child maintenance was prevented from selling his house by the Child Maintenance and Enforcement Commission to stop him from concealing the proceeds of the sale. In the first case of its kind, the Commission applied for a freezing order after the man put his house on the market using a popular property advertising website.