Siptu is to proceed this week with legal action to secure the full HSE internal audit report which alleged that there were no accounts or receipts attached to a €2.35m health training fund channelled through an account bearing the union's name between 2002 and 2009.

Siptu's legal move comes as the HSE appointed the former head of employers' group Ibec, Turlough O'Sullivan, to conduct an internal independent inquiry. O'Sullivan's appointment was seen as an effort to bring calm to an expenses 'scandal' that is now the subject of four separate investigations. O'Sullivan's investigation is mirrored by Siptu's own internal inquiry into a union official.

Siptu trustees have brought in consultants and auditors Mazars to try and find where the money went. The HSE has also made a formal complaint to the gardaí, while the Public Accounts Committee said it will investigate any possible misuse of public money.

The HSE claims the €2.35m, which was part of a larger €60m training fund for lower-paid medical staff, was used to fund 31 foreign study trips for those involved but there are no receipts or records to explain how the money was spent and who went on the trips.