Civil servants demanding a shorter working week say they want to focus on returning to a six-hour and 57-minute working day after it was increased by around 27 minutes in 2013.
The Finance Minister claims that 12,000 extra workers would be needed if the hours are reduced.
The issue will be debated at Forsa Trade Union's first ever civil service conference today.
"It was one of a number of cuts and changes to working conditions introduced during the economic crisis," said Bernard Harbour of Forsa.
"The motions that we are looking at on this issue today at the conference are calling for a reduction in working time.
"I would be amazed if they weren't passed at the conference and that means that the issue will then go on to the agenda when we negotiate the next public service agreement."