The courts service risks losing around £1.4 billion in uncollected fines and other financial penalties by not being able to properly account for them, according to the National Audit Office, which laid part of the blame with the beleagured £444 million Libra system.

The NAO said "limitations" in the case management system have contributed towards the "inability" of courts "to provide information at an individual transactions level to support the accounts".

Libra, implemented by Fujitsu, costs £10 million a year to run. The NAO said the Ministry of Justice and the Courts Service have informed it that they may not be able to address the accounting records issue fully until Libra and other systems "are significantly enhanced or replaced".

In a report to parliament, NAO auditor general Amyas Morse said HM Courts Service has been "unable to provide proper accounting records supporting fines, confiscation orders and penalties". This meant he "could not give an audit opinion on whether transactions and balances were complete, proper and appropriately raised".

The NAO said total outstanding debt in respect of fines, confiscation orders and penalties at the end of March 2011 was £1.9 billion (which increased from £1.5 billion in the previous year), while "only £457 million is recognised in the account as receivable". It said "the difference of £1.4 billion represents management's estimate of debt that is at risk".

The non-collection of fines has been a perrenial problem for the courts service, with many owing the money realising enforcement action can take many months or simply not initiated.

Morse said: "Because of limitations in the underlying systems, HM Courts Service has not been able to provide me with proper accounting records relating to the collection of fines, confiscation orders and penalties. I have therefore disclaimed my audit opinion on its accounts."