The State was facing an estimated medical negligence bill of nearly a billion euro in respect of all active claims at the end of 2012, according to a report from the Comptroller and Auditor General (C&AG).

The C&AG 2012 report on the accounts for the public service states that the estimated potential liability in respect of all active clinical claims at the end of 2012 was €970 million.

The State Claims Agency (SCA), which handles claims against the health service through its Clinical Indemnity Scheme (CIS) includes a 'margin of comfort' of up to 20% in its estimates of the potential liability associated with individual claims.

As a result, the potential liability in respect of active claims may be overstated, according to the report.

The report says the number of clinical indemnity claims by the SCA has increased year on year, with the case- load at the end of 2012 (excluding the DePuy hip implant cases) representing an increase of over 45% since the end of 2008.

The C&AG report also says over the same period, the average time taken to resolve cases has also risen significantly.

Direct costs have increased to an average of €190,000 per case, which is nearly double the 2009 equivalent figure.

There were 230 claims made in 2012 relating to the faulty hip replacement implant made by De Puy Orthopaedics.

While demand under the CIS, in terms of new claims received, increased from about 500 in 2008 to about 830 in 2012 (including about 230 DePuy cases), the number of cases resolved by the SCA remained steady, at between 400 and 450 per year.

The or noted that the HSE does not publish a schedule of the individual healthcare facilities in respect of which claims are settled, or are outstanding.

The C&AG said the Accounting Officer of the HSE had stated that the publication of such information could encourage the generation of 'league tables' which it considered would not be constructive, and could have the unintended consequence of discouraging the reporting by healthcare facilities of adverse events.

Meanwhile, the report states that the reason for part of a cost overrun by the HSE on the medical card and other community schemes - amounting to around €90 million - are unclear.

Referring to the health service regularly running over budget in recent years, the report says budgeting for future periods is subject to error because of inherent uncertainty and factors that may be outside the health service budget holders' control.

It said the estimates in respect of the HSE for 2012 did not appear to have taken account sufficiently of the underlying cost drivers in some key expenditure areas.

"There is scope for the HSE to carry out more thorough analysis of the demand for services, and of the associated costs, and of underlying trends," according to the C&AG.