Fianna Fáil say it's too soon to rule out a €5 increase in social welfare payments in the budget.
It comes after reports over the weekend that the Finance Minister has ruled out such an increase in pension, dole and carer's payments.
Pascal Donohoe is framing the budget on the basis of a no-deal Brexit.
Willie O'Dea, Fianna Fáil's spokesperson on social protection, disagrees with the government's approach:
"I deplore the Government deliberately leaking a story to the Sunday Times yesterday. It was obviously a leak from the Government to create the impression that this was all done and dusted," he said.
"This hasn't even been properly thrashed out yet in the negotiations between Fianna Fáil and Fine Gael.
"I've spoken to our people, and they haven't even gone into negotiating figures with the Government yet.
"The Budget has to be agreed. Whatever the Fianna Fáil party as a whole decides - I'm a democrat, I have to go along with that.
"The most vulnerable people in this country should be assisted."
- Additional reporting Vivienne Clarke