Rules govern qualifications for top-ups
Pension top-ups and special deals can be approved by the Government for a wide variety of reasons.
These range from legal wrangling to the abolition of a public servant's office.
For example, under Brian Cowen's tenure, senior management in regional health boards received a special pension deal when their offices were abolished and the new Health Service Executive was set up.
Other deals were done under specific acts or special schemes outlined by the Government.
The Superannuation and Pensions Act, 1963, entitles a civil servant to additional years of service on their pension package if their office is abolished.
Many of the deals approved over the past decade fell under this act.
Separately, guidelines for a special scheme for chief executives of semi-state bodies were outlined by the Department of Finance in 1998. But to qualify for the terms of the deal, specific terms and conditions were put in place.
The Dail's spending watchdog will now probe why four such packages were cleared by the Government even though the conditions were not met.