The Taoiseach has said the Croke Park Agreement will be honoured in full.
Enda Kenny said it will not be subject to what he called unilateral re-negotiation.
Mr Kenny said his Government wanted to speed up the implementation of the existing agreement in order to achieve as many savings as possible from it.
He said he would continue to meet with unions and the implementation body to get the best from the deal.
Fianna Fáil said if it came down to a clear choice between protecting the vulnerable or protecting the most senior well paid public servants, the vulnerable would have to be protected.
Finance spokesperson Michael McGrath said at this point the Government seemed to be committed to honouring the Agreement until 2014, but the mixed messages on it were not fair on anyone.
He said if the Government wanted to protect all elements of the Agreement, including top public servants, it could come at a high price for the most vulnerable in the country.
He said that was a choice that might well have to be made over the next couple of months, but in his view, the disabled, sick and the elderly must be the priority.
However, Mr McGrath declined to specify a salary scale below which public servants pay might be protected.
Earlier, Minister for Communications Pat Rabbitte said there is merit in re-examining the terms of the agreement in the context of the upcoming Budget.
Speaking on RTÉ's Morning Ireland, Mr Rabbitte said Ireland's financial situation was such that the deal should be looked at to see if any extra elements could be included.
He said the Government acknowledged that it must keep its part of the Croke Park Agreement, and said that the savings achieved had been better than planned.
However, Mr Rabbitte said that because of a number of reasons, such as the instability of the euro, Ireland still faced a difficult economic environment, and that the consumer and retail economy was very flat.
He said the Government had a particularly difficult Budget to deliver in December.
He said it was his view that, "if the Government was so-minded", that new elements should be introduced into the discussions and the parties to the agreement should be convened to consider the new situation "without prescription".
Mr Rabbitte said there was a facility under the existing agreement to convene the parties and discuss the overall situation and he said he thought that might be productive.
Meanwhile, Minister for Children Frances Fitzgerald has said that invoking a clause in the Croke Park Agreement to re-examine the current agreement on public sector pay remains an option.
However, she said that more can be achieved under the current agreement and that the Government needs to work on doing that across all departments.
Clause 1.28 of the Croke Park Agreement on public service pay and conditions states: "The implementation of this agreement is subject to no currently unforeseen budgetary deterioration."
However, Ms Fitzgerald said that she does not believe there is flexibility under the current agreement on public sector pay to look at issues, such as increments or pensions, as areas for potential savings.
She said that whether or not a new agreement on public sector pay would be negotiated for 2014 when the agreement expires is "a decision for Government".
Agreement not fit for purpose - McGinty
Also speaking on Morning Ireland, IBEC Director of Industrial Relations Brendan McGinty called for a renegotiation of the Croke Park Agreement.
He said it is not "fit for purpose" and that there was provision for the Government to negotiate with the unions to change the deal.
Mr McGinty singled out pension arrangements for current public service employees, as well as allowances, as two fundamental issues that employers believe need to be tackled.
He said: "The burden of the pension changes that have been agreed under the agreement falls on new entrants.
“We believe that issue is going to have to be engaged in for serving public servants because of the scale of liability to the Exchequer, where you're looking at possibly a liability of about €130bn.
"That's not sustainable, nor is the issue of allowances in the current environment."
Cost reductions have been met - Cody
IMPACT General Secretary Shay Cody said cost reductions under the agreement had been met, often ahead of schedule.
Mr Cody said there are provisions within the agreement to address outstanding issues or potential savings.
"The great bulk of allowances that are paid in the public service are paid to people because they work night shifts, they work 24-hour cycles, they work seven-day cycles," he said.
"There are some allowances that the Government are reviewing and the trade unions have simply said to the Government 'Come forward with your proposals, if we can live with them, we can live with them.
“If we can't live with them, we have a mechanism under Croke Park that we can test the justification for those, in front of the Labour Court or some arbitration body'."
Mr Cody also said he agreed with Brendan Howlin's assertion last week that some managers were using the agreement not to be proactive.