There have been calls on the parties negotiating the programme for government to clarify if pre-election pledges not to increase the pension age to 67 from next year will be honoured.
Labour's Ged Nash said the newly published revised estimate for the Department of Employment Affairs and Social Protection raised serious questions about whether the pension age increase will still be stopped.
Two sources close to the talks process have indicated to RTÉ News that delaying the raising of the pension age from January next could be difficult to achieve given the changed economic circumstances.
The matter may be discussed in negotiations between the Green Party, Fianna Fáil and Fine Gael tomorrow.
The pension age was one of the biggest issues during the general election campaign earlier this year.
At the time, both Fianna Fáil and the Green Party vowed to postpone plans to change the pension age from 66 to 67.
Fine Gael said the age would increase but there would be a transition payment paid to people who retired before they turned 67.
Sinn Féin promised to bring the pension age back to 65.