The confidence-and-supply deal keeping the Government in place could end if there is a Brexit deal, senior Fianna Fáil TDs have warned.

Limerick TD Willie O’Dea said his party could walk away from the deal, which would cause an election, if there is a stable Brexit and another issue – such as overspending on the national children’s hospital – damages faith in the Government.

Niall Collins, another frontbench member, said the survival of the Government could be counted in “weeks or months” once there is clarity on Brexit.

Their views reflect a growing unease within Fianna Fáil about the deal, which Micheál Martin extended for another year before Christmas.

The Fianna Fáil leader has in recent days reiterated his commitment to facilitating the passage of another budget. The deal struck between Mr Martin and Taoiseach Leo Varadkar envisages the next general election being held in the spring or summer of next year.

However, many Fianna Fáil TDs believe that a fourth budget is unlikely to be agreed between the parties. The views of the Fianna Fáil membership will be keenly watched at the party’s ard fheis in Dublin this weekend.

Mr O’Dea said Fianna Fáil should vigorously oppose the Government if uncertainty around Brexit is removed, and called the overrun on the national children’s hospital a “debacle”.

“You could walk away from the supply and confidence if the circumstances warranted it,” Mr O’Dea said.

However, he said this would depend on the Brexit process, adding that an extension of the negotiating period from the anticipated day of the UK’s exit on March 29th until June, as has been mooted, would mean political stability is still needed.

Mr Collins, the party’s foreign affairs spokesman, said: “Once there is clarity on Brexit, you are looking at an election within weeks or months.”

Barry Andrews, Fianna Fáil’s Dublin candidate for the European Parliament, last night also cast doubt on the future of the agreement. “I am not sure we can maintain another budget but it is not for me to decide that,” he said.

Others expressed similar sentiments privately. “The minute a [Brexit] deal is ratified, people will be ready for the off,” said another frontbench member, adding there is an “anxiousness to go to the country” and that it is “hard to see” the Government lasting beyond September or October.

Michael McGrath, the finance spokesman, said the decision to extend confidence and supply has been proven correct.

“The party’s commitment to an extension of the confidence-and-supply agreement to bring the country through that period of Brexit uncertainty remains in place. That decision has broad support across the party and in my view among the general public.”