There is "huge unrest" in the Green Party's grassroots over Fianna Fáil and Fine Gael's response to their government formation demands.
he letter sent by Fianna Fáil leader Micheál Martin and Taoiseach Leo Varadkar in response to 17 questions posed by the Green Party has been heavily criticised by Greens around the country, sparking serious doubts that party members would approve a coalition deal.
Green Party TDs also have concerns about Mr Martin and Mr Varadkar's letter, and a decision on whether or not to rebuff the Civil War parties' invitation to talks could come as early as today.
Fianna Fáil and Fine Gael stopped short of committing to the Greens' key demand of a more ambitious 7pc-a-year target for reducing greenhouse gas. Mr Martin and Mr Varadkar invited Green leader Eamon Ryan to negotiations to discuss how the target can be achieved.
But they also warned that no party will want to introduce climate action measures that may jeopardise employment, increase poverty or affect rural and regional development.
Mr Varadkar last night said he didn't want to commit to "a target that can't be done".
But he also didn't rule out the 7pc target and said he was keen to enter talks.
A two-hour meeting of the Greens' parliamentary party ended with a decision to reflect further on the letter.
TDs and senators will meet again today to thrash out whether to seek further clarifications or reject the invitation to enter talks outright.
A Green Party source said there was "huge unrest" among the party's grassroots and, as things stand, they did not believe party members would vote with the two-thirds majority required to enter government.
Aside from the carbon emissions issue, there is said to be concern at proposals that would still see private homes built on State land and a "fudge" in the Greens' demand for a 2:1 breakdown in spending favouring public transport over roads infrastructure.
Reaction among TDs and senators was said to be "mixed".
Wicklow TD Steven Matthews told the Irish Independent the two larger parties "have committed to some of our objectives".
But he said "more detail and much firmer commitment is required" in relation to the Greens' demand for 7pc-per-year reduction in carbon emissions, as well as demands relating to housing and the scrapping of a planned Liquefied Natural Gas (LNG) terminal project.
Another TD, Neasa Hourigan, shared a Twitter post by Sinn Féin TD Eoin Ó Broin in which he criticised the housing proposals made by Fianna Fáil/Fine Gael in their letter.
The party's youth wing, Young Greens, has argued that Fianna Fáil and Fine Gael aren't interested in the climate crisis and just want "a mudguard". Prominent party member Saoirse McHugh said the letter was "absolutely wocious" and added, "what a joke".
Cork City councillor Lorna Bogue said if Fianna Fáil and Fine Gael are still not committing to the 7pc carbon emissions reduction target "it's clear the Greens should walk".