Over 2,600 Green Party members are registered to take part in Thursday's online conference on the programme for government, with sources saying it is "impossible to say" whether members will approve the deal by the two-thirds required.
It is understood that around 500 of those taking part are newer members who will not be eligible to vote, but will still take part in the online conference, where party leader Eamon Ryan will attempt to persuade his members of the deal's merits.
It is understood that Mr Ryan will call for the party to show unity and approve the deal. Sources say that the fact that the vote takes in Green Party membership on the entire island may complicate things, as it means that 550 Northern Greens will be entitled to vote, around 20% of the membership. What way these votes go is "anybody's guess" according to one party source.
However, there has been division within the party in recent days, as three TDs abstained from the parliamentary party vote on the issue and one of the negotiating team, Dublin Central TD Neasa Hourigan, said that she was unsure than she could vote in favour.
Cork City South East councillor Lorna Bogue says that the deal represents "Green flavoured austerity" and said that the party had a choice to "be a watchdog or a lapdog".
"I'm worried about the basis of the policy. My concern is that the policies which underly the document are austerity. They don't use that term, but if you read the document, the economic approach is austerity. And I won't vote for something that I know to be incorrect.
"The deal says there will be no increase in taxes but give a tax cut to self-employed people earning over €100,000 and at the same time talks about investment in services. There is no commitment to reinvest windfalls, with all of that going to service the deficit.
"This would be Green-flavoured austerity and would associate environmental action with people getting hit by taxes."
Clondalkin councillor Peter Kavanagh said that he was leaning towards voting no but said "credit is due" to the negotiating team for working out a greener programme for government than was possible without the party.
"While I'll make up my mind after Convention, I feel that our concessions outweigh our gains and I don't see this as being the best option for the country."
Mr Kavanagh said that he was particularly disappointed that a €22m demand for the Irish Language and the Gaeltacht was not included.
"It is a small amount of money comparatively speaking, but would be utterly transformative for the language and for marginalised communities and we were unable to secure even this small commitment."
Dublin MEP Ciarán Cuffe has said that his party should “grasp this nettle” and the extraordinary opportunity to promote a green agenda “even if Fine Gael and Fianna Fáil are not our natural bedfellows.”
Mr Cuffe said that the Green Party “can’t sit out this one” until they find an exact political alignment. “We can stand on the sidelines saying ‘do something’ or roll up our sleeves and get in.”