The Finance Minister Michael Noonan has said a new series of cuts being considered by the Government for next year will go outside of the terms of the Croke Park Agreement.
Government departments have been written to and asked to consider "bold and unpalatable" measures to save money.
In a letter to departments, the secretary general of the Department of Public Expenditure has asked Government to identify services that could be outsourced or transferred to the private sector.
The proposal will worry public sector unions who have signed up to the Croke Park Agreement which guarantees certain terms and conditions in return for increased productivity.
Mr Noonan said: "Croke Park was one set of agreements about specific issues. The expenditure review ranges across all items of expenditure, so of course it will go beyond the parameters of Croke Park.
"But it is not contradicting Croke Park, if you take the distinction."