Taoiseach Leo Varadkar has said he cannot guarantee the next election will not be called before the planned 2020 date, adding that he may not win an early general election.
The Government relies on a confidence-and-supply deal between Mr Varadkar's Fine Gael party and Fianna Fáil.
There was speculation earlier this year that the two parties would not be able to reach an agreement to extend the deal.
It entails support for legislation implementing next year's budget and enables the minority coalition Government to operate for another 12 months.
A new deal was confirmed earlier this month, but Mr Varadkar said he cannot rule out calling a general election before the planned date in 2020.
"The situation is that we've agreed that there won't be an election, given the uncertainty around Brexit, and that we, as Fine Gael and independents in government, that with Fianna Fáil we will try to negotiate another budget," he said.
"There's always the possibility that we won't be able to negotiate that budget. I can't give an absolute guarantee.
"What I sought was that we agree an election date in 2020. Fianna Fáil decided not to accept that, so that was an offer that was on the table - an agreed election date in 2020.
"Fianna Fáil decided not to accept that and proposed an alternative which was that we negotiate one more budget."
Mr Varadkar also said he is conscious that if there is an early election, he may not win it.
"People might get elected to the European Parliament for example, and that would be a vote gone," he said.
"Sadly, politicians, on occasion, become sick and die.
"The fundamental question when you're in government is: are you able to govern? Are you able to get your legislative programme through? Are you able to implement your policies to the benefit of the Irish people? And that's the fundamental question.
"So as long as we can do that, we're in government. And I'm very conscious that if there was an election, I mightn't win it."
Fianna Fáil leader Micheál Martin previously said it was in the national interest to have political stability as Ireland faced the prospect of a no-deal Brexit.
The historic pact between two parties was struck following the inconclusive 2016 general election and has lasted for three budgets.
Following the last budget in October, negotiating teams from both parties engaged in talks aimed at securing an extension.
The renewed deal will last the duration of 2019.
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