TWO-thirds of Central Bank staff are contracted to work just 32.5 hours a week compared with a norm of 39 hours across the private sector.
The state agency tasked with overseeing the biggest banking crisis in the history of the country last night confirmed 699 of its staff worked these hours.
The revelation led to employers' group IBEC warning that working weeks of 32 and 35 hours were "no longer tenable" in the public sector.
It also comes as the Government faces intense pressure to deliver major changes to public sector work practices under the Croke Park Agreement.
The Central Bank confirmed 65pc of its administrative and professional staff -- regardless of grade -- were employed on a 32.5-hour-a-week contract, while 35pc work a 35-hour week. The hours exclude lunch, but are well below private sector norms.
The Central Bank accepted the 32.5-hour week was "not sustainable" and said it was seeking to reduce the number of staff on such contracts.
IBEC director Brendan McGinty said: "In the vast majority of cases in the private sector, 39 hours would be fairly standard, and you're talking about paid hours exclusive of the lunch break."
Mr McGinty also said many lunch breaks in the private sector had been pared back from one hour.
"The reality is that average levels in the public sector have been significantly behind the private sector for some years, and this is no longer tenable," he added.
The Central Bank, which has an independent status due to its role as the watchdog for the financial system, is not part of the Croke Park deal.
However, a review of the deal is due to be carried out by the implementation body to discover if it is delivering the necessary savings.
The Government wants to be able to show savings from the deal to meet its election promise to reduce the burden of the universal social charge on the lowest paid workers.
The working week revelations come after an Irish Independent investigation revealed highly paid county managers enjoy annual leave entitlements of up to 43 days a year.
The local authority bosses subsequently volunteered to accept a cap of 32 days on holiday entitlements, which is still well above the 25-day average among private sector managers.
The Central Bank professional and administrative staff on a 32.5-hour week earn salaries ranging from about €28,000 to almost €67,000. Staff employed since December 2008 are on 35-hour contracts.
Central Bank workers must take a minimum of a half-hour lunch, but the remaining 30 minutes is clocked up as flexitime, which can be converted into a maximum of one day off a month.
A Central Bank spokeswoman last night insisted that, in practice, management and many staff worked more than their contracted hours.
She said while the Central Bank was not a signatory to the Croke Park Agreement, progress had been achieved in the past two years to change working hours.
As a result, she said the ratio of those on the lower-hour contracts should drop from 65pc to 56pc by the end of the year.
However, it is understood the longer 35-hour contracts are only being introduced for existing staff if they are promoted and new recruits.
The Central Bank is headed by Governor Patrick Honohan and its 1,300 staff includes those employed by Financial Regulator Matthew Elderfield.
Meanwhile, about 400 workers attended a May Day protest in Dublin yesterday to signal their opposition to any further pay cuts.
SIPTU general president Jack O'Connor called for a levy on incomes of more than €100,000 to raise €1bn for job creation.
He suggested a dividend could be given back to those who were levied if the State managed to make a return on the money it raised.