Nothing can be ruled out, including a second general election this year, if parties do not vote to pass the draft government deal, the Tanaiste has said.
Simon Coveney said, however, that he is a positive person and believes the deal can be approved.
The outcome of the membership votes among the three parties will be announced on Friday.
The Green Party has the highest threshold of the three parties to secure the approval of its membership.
Two thirds of members registered to vote on the proposals must back the deal.
However, one of the TDs who negotiated the deal, Neasa Hourigan, has said she will vote no on the deal while a number of Green members have voiced their concern about it.
The leader of the Green Party in Northern Ireland, Clare Bailey, has also called for a no vote.
Mr Coveney said he is still hopeful the deal will be passed.
"I think we will have to have that debate when it happens. I'm a positive person and I believe we can get this done this week and that is what the country wants us to do," Mr Coveney told RTE Morning Ireland.
Asked if another election could be on the cards if the deal does not pass, he said: "Well I mean we can't rule out anything. Our focus will be on getting this deal passed and putting in place a government that can work for people when the country needs it."
He said this is a difficult week for Fine Gael, Fianna Fail and the Green Party because there is division among members and politicians about the deal.
He said: "In many ways, within Fine Gael there are lots of people who still find it difficult to contemplate going into government with Fianna Fail in particular.
"Politics has changed and if Fine Gael defines itself by its past and its past relationship with Fianna Fail then I believe the electorate will move away from us. We have got to define ourselves by what we want for the future."
When asked about opposition to the deal, voiced by Ms Hourigan, he said she was part of the negotiating team that signed off on the deal.
He said: "She did not get everything she wanted in the deal... nor did I".
The results of all three party votes will be announced on Friday and all three must back the deal in order for Fianna Fail leader Micheal Martin to be elected Taoiseach when the Dail sits this Saturday.
'The first tears to dry are the tears of gratitude," the 19th- century American showman PT Barnum is quoted as saying. And Leo Varadkar got a lesson in the verity of that aphorism on election day.
Micheal Martin, Leo Varadkar and Eamon Ryan will meet this week to finalise a restructuring of government departments and a raft of new ministerial appointments. Here's the cabinet they could end up picking: