Fine Gael Finance Spokesperson Richard Bruton has said using unpaid leave as a solution to the crisis in the public finances was not credible.
Speaking on RTÉ's Six-One News, Mr Bruton said you cannot deliver the same services with 5% less man hours.
He said it would be a mistake to see a recovery in the latest tax figures and what was missing from the Government was a plan for building confidence.
Earlier, the Taoiseach said union proposals for reducing the public service pay and pensions bill through unpaid leave do not provide the basis for agreement in their present form.
Brian Cowen told the Dáil that the Government was still determined to secure savings of the order of €1.3bn next year.
He said the proposals for unpaid leave put forward by the unions did not go far enough.
The postponement of the day of industrial action, which was due to take place tomorrow, was also welcomed by the Taoiseach.
The Taoiseach told Fine Gael leader Enda Kenny that the Government remains committed to savings of €1.3bn next year - and those savings would have to be permanent.
Mr Kenny said the Government had abdicated its responsibility to sort out the economic mess. He said it was not possible to achieve permanent savings by having 12 extra leave days.
Mr Cowen told Labour leader Eamon Gilmore the savings would have to be made, whether there was an agreement by Budget Day or not, because the Government did not have the money to pay the public service pay bill.
Mr Gilmore described the Government's strategy as muddled, saying the Taoiseach had left agreement too late.
Speaking to RTÉ News in Brussels, Minister for Finance Brian Lenihan said the public service unpaid leave proposal was an interesting idea but was by no means agreed.
When asked about public sector pay cuts, he declined to rule them in or out.
Mr Lenihan said: 'Clear and measured savings must be secured if there is to be an agreement.'
Strike deferred
Talks between union representatives and the Government on the proposed pay deal at Government Buildings have adjourned for the night.
The public sector strike was deferred after yesterday's talks in which the Government acknowledged that savings from staff taking 12 days annual unpaid leave next year could be the basis for cost savings being sought.
SIPTU's Patricia King, who is Vice-President of ICTU, said that talks have 'started to progress' but that difficulties remain.
Liam Doran, General Secretary of the Irish Nurses' Organisation, said that 'a lot of work remains to be done'.
He added that the question of transformation remains critical, as the 'Government's policy will lead to a smaller public service', and result in a 'significant shift' in the provision of health care.
Earlier, IBEC Director General Danny McCoy dismissed the proposed pay deal between Government and unions as a 'fudge' and insisted 'it is not a credible solution'.
Teachers' Union of Ireland General Secretary Peter McMenamin said there was broad agreement in principle on the proposal.
