The leaders of both Fianna Fáil and Fine Gael have warned there is "no plan B" in the event of the programme for government being rejected.
Party members are voting on the deal, with both parties expected to pass it. However, the members of the Green Party are also voting with sources in that party saying that it is "too close call".
Speaking to RTÉ Morning Ireland, Micheál Martin said that there is no alternative on the table.
"An enormous amount of time has been put into the negotiations to get this programme for government together, there is no magic Plan B”.
Mr Martin added that it is “uncertain" what will happen if this programme for government is not agreed, but said he would not speculate.
Mr Martin said that another election was a possibility but he felt that people would be angry if there was one.
In the context of Covid-19, we do not need another general election. And I think the Irish people would be very angry if a general election was visited upon them.
In a separate interview with Newstalk, Leo Varadkar said the rejection of the deal would lead to a "political crisis". He said that the parties of the coalition received a majority of both votes and seats and this mandated them to seek a deal.
“I know there are some people in my party who are counselling me and advising me to have a Plan B on the shelf, but I decided not to that because we entered these coalition talks in good faith with Fianna Fáil and the Greens.
"The three parties together won 51% of the vote in the election.
"I know there is a party out there that thinks 24.5% is a majority – it’s not, 50 plus one is a majority and that is what we have.
“If it is defeated, we will have to sit down over the weekend and see what the options are.”