The Dail's public spending watchdog is going to force a retired SIPTU official to appear before its investigation into a "slush fund".
It is believed to be the first time that a Dail committee has used the power of "compellability" since it was provided for in legislation in 1997.
Former SIPTU national industrial secretary Matt Merrigan ran a bank account which received over €4m in funds from the taxpayer over a seven-year period.
Mr Merrigan, who retired last year, declined a request to appear before the Public Accounts Committee's hearings into the operation of the fund. But the committee has now decided to use its powers of compellability to get Mr Merrigan to appear.
Under the act, anyone who refuses to appear can be fined up to €25,400 or imprisoned for up to two years.
Labour TD Derek Nolan, who called for the move, said that it was essential to get a full account of what had happened.
"If we don't get answers, we won't get a full picture of what happened and be able to make sure it doesn't happen again," he said.
The committee is sending its request to the Dail's Committee on Procedures and Privileges. If that committee approves its request, it will then contact Mr Merrigan to request him to appear.