The Labour Party has said that it will not take part in formal discussions with Fianna Fáil and Fine Gael on a programme for government.
Other parties including the Social Democrats and Aontu have also ruled themselves out of government formation talks.
In a letter to the leaders of Fianna Fáil and Fine Gael, Labour leader Alan Kelly said it was the party's view that talks with the Green Party should be given the space and time to reach a conclusion.
He also said it was not clear that a united position has been adopted on future economic and fiscal policy to rebuild society and the economy and he said that was at odds with Labour's approach.
Mr Kelly said it was Fianna Fáil and Fine Gael's goal to achieve a "well resourced, properly functioning and responsive State", but he said it was "premature and unrealistic" to rule out using taxation to achieve this.
Fine Gael leader Leo Varadkar said he was "disappointed" that Labour had ruled itself out of talks on government formation.
He said the party joined government at a difficult time in 2011 and were badly punished "perhaps unfairly" by the electorate.
On the Social Democrats, he said the party would not meet to talk about forming a government.
"I think that is a pity but it is not a surprise.
"It is a party that ultimately was formed by people from the Labour Party who didn't want to join a government before so it was always unlikely that they would want to on this occasion," the Taoiseach said.
He said talks between Fianna Fáil, Fine Gael and the Greens were ongoing and were going well.
The Taoiseach said he was confident it would be possible to negotiate a programme for government before the end of the month.
Mr Varadkar said it would then be put to the parties for ratification and be in a position to form a new government by the middle of June.
He warned that it would not be an easy time to be in government and he said the economic consequences of the Covid-19 emergency would be very severe in terms of jobs being lost and businesses that will not open again.