The Republic of Ireland's main opposition party has described Leo Varadkar's hopes of renewing the parties' confidence-and-supply deal as "a distraction".
The taoiseach (Irish prime minister) wrote to Fianna Fáil leader Micheál Martin on Friday asking to extend the arrangement until summer 2020.
Mr Varadkar released a copy of the letter on social media on Tuesday.
Both parties are set to meet on Wednesday to discuss the 2019 budget.
Irish national broadcaster RTÉ reported that Fine Gael want a two-year guarantee for stability., and that Mr Varadkar is ready to appoint a team to begin talks "immediately".
The current Fine Gael-led government was formed following an inconclusive general election in March 2016, and many subsequent weeks of negotiations.
Fianna Fáil agreed to support the government for three budgets and in confidence motions.
In Mr Varadkar's letter, he said a government "cannot function if it is living on borrowed time" and that such uncertainty weakens the government's hand in the Brexit talks.
But a spokesman for Fianna Fáil told RTÉ that the letter was "a kite that should be left to fly away with the wind".
He added that the priority is the upcoming budget talks, which are just five weeks away.
Any discussions on extending the confidence-and-supply agreement could only happen after that, he said.
Mr Martin made similar comments recently that the confidence-and-supply agreement talks can only begin after the budget.
'Interest of the people'
Mr Varadkar's letter argues that "much has changed" since the two parties struck an agreement in 2016.
The deal saw Fianna Fáil agree to facilitate a Fine Gael-led minority government under specific terms, while acting as an independent opposition party.
Mr Varadkar said Brexit, an overheated economy, changes to the international corporate tax landscape and possible disruptions to the global trading system pose significant threats to the country.
"Without a doubt, there is more to do," he wrote.
"It is my view that a government cannot function or work in the interests of the people if it is living on borrowed time.
"A government cannot function if it does not know if it will last from week-to-week or month-to-month, if it does not know what will happen to its programme and legislative agenda the day after budget day or the day the Finance Bill is passed," he added.