Fine Gael has announced that it is "preparing to go into the Opposition" and will not form a part of the next government.
It comes after a six-hour meeting of the parliamentary party today.
Outgoing Taoiseach Leo Varadkar told the meeting that he "relishes the challenge to lead a strong and effective Opposition for the benefit of the country".
The party said in a statement this evening that it will hold the new government to account.
It said the parliamentary party "agreed that the onus is on Sinn Féin to form a Government of the left with the support of independents".
"Sinn Féin has an obligation to the people who voted for it to show whether or not it can honour the extraordinary promises they made.
"If Sinn Féin fails in that challenge then the onus passes to Fianna Fáil to form a government with them, and or with the Greens, Labour and Social Democrat parties and independents."
Mr Varadkar will engage with the other parties to discuss the outcome of the election.
Fine Gael said no further negotiations on forming a government will be done without the input of the parliamentary party.
They will meet again next week.
