The Minister for Finance, Mr McCreevy, has announced a range of reforms designed to modernise public service pensions.
The reforms, which are mainly technical in nature, will come at "modest" cost to the Exchequer, according to a Department of Finance spokesman.
They come in addition to changes introduced after last year's Budget, which raised the minimum pension age to 65 and removed the compulsory retirement age for most new public servants.
Under new rules, public servants who wish to retire early at the age of 50 or 55 will be able to draw down "actuarially reduced superannuation benefits".
This will mean that, rather than waiting until age 60 or 65 to access their "preserved" benefits, early retirees will be able to access an actuarially reduced pension immediately.
The facility will be available to both serving staff and those who retired with preserved benefits after April 1st this year.
The changes will also allow for a new calculation to be used when integrating social insurance with public sector pensions.
This measure, which will benefit a relatively small group, is designed to boost the retirement income of lower-paid public servants who pay the full rate of PRSI.
The new rules will benefit teachers too, with the spouses' and children's scheme to be opened to primary and secondary teachers for the first time. The scheme will be open to teachers working at the end of March this year who wish to contribute.