Fianna Fáil says a crunch time will come when a Government needs to be formed.
The Taoiseach says it is possible there will be one in place by June - but Fine Gael and Fianna Fáil need the support of others.
The Green Party says there needs to be a 7% reduction in greenhouse gases, which may mean increased carbon taxes.
Fianna Fáil's Thomas Byrne says decisions need to be made.
He says: "At some point, a government will have to be in place. I think there is an opportunity now to talk about the formation of a Government and the program of government, what's contained in it.
"And I think there is an openness of mind certainly on the part of Fianna Fáil to ensure that we get the best possible social and economic recovery for this country once this Covid crisis dissipates."
Today Taoiseach Leo Varadkar urged the Greens to enter formal coalition talks as he expressed a willingness to meet their carbon emissions target.
Leo Varadkar, who said he did not think a new government will be formed until June at the earliest, said Ireland’s economic recovery from Covid-19 could be “green not brown”.