The President of SIPTU has said the payment of money by the Department of Health into an unauthorised SIPTU account is "immensely damaging" to the union.
Two separate payments of €190,000 and one of €40,000 were made into an account controlled by senior SIPTU official Matt Merrigan, and a senior member of the union, Jack Kelly.
Yesterday, an Oireachtas committee heard that the money cannot now be traced.
SIPTU President Jack O'Connor has said the union was absolutely responsible for getting to the bottom of the issue, because the account was set up by a SIPTU employee and because the union had a responsibility to use state money appropriately.
"The greatest omission and failure on our part is to protect the interests of the workers' organisations in this situation, and we fully accept responsibility for it," he said.