DUBLIN (Reuters) - Ireland’s prime minister on Tuesday formally proposed extending a deal with the main opposition party to back his minority government beyond this year, asking it to agree an election date for the summer of 2020.

FILE PHOTO: Rugby Union - Rugby World Cup 2023 host country candidates press conference - Royal Garden Hotel, London, Britain - September 25, 2017 Irish politician Leo Varadkar during the press conference Action Images via Reuters/Paul Childs

Leo Varadkar’s Fine Gael-led government operates through a “confidence and supply” deal with the largest opposition party, Fianna Fail, which has agreed to abstain from opposition-driven votes against the government until the end of 2018.

Varadkar said earlier this year he wanted to renew the pact and that talks to do so should start well ahead of its expiry. In a letter to Fianna Fail leader Micheal Martin published on Tuesday, he said he was ready to start negotiations immediately.

“A government cannot function properly if it does not know if it will last from week to week, month to month, or if it does not know what will happen the day after the budget,” Varadkar said, referring to a budget for 2019 which will be presented on October 9.

“Such uncertainty weakens our hand in Brexit talks, at a time of increasing international uncertainty.”

Some senior Fianna Fail lawmakers have said they are open to extending the deal for another year, but Martin reiterated in a response published by his party on Tuesday that he would not begin talks on a possible extension until after the budget was announced.

He did not respond directly to Varadkar’s call to set a 2020 election date.

With Fine Gael leading Fianna Fail in opinion polls by a wider margin than at the last election in 2016, a senior Fianna Fail member of parliament who negotiated the original pact accused Varadkar of trying to orchestrate a snap election.

“I think the letter is a distraction and is unnecessarily creating instability,” Jim O’Callaghan told national broadcaster RTE.

“What we need to do now is get agreement on the next budget. After that, we have no difficulty sitting down and discussing whether it should be renewed or not,” he added.

“My own view, and maybe I’ve a cynical mind, is that I believe the Taoiseach (Prime Minister) wants to have a general election in October or November, and that’s why I think he is orchestrating a mechanism to get out of it (the ‘confidence and supply’ deal).”