A Fianna Fáil TD says he is unsure if a programme for government between The Green Party and Fine Gael will get the backing of the party.
The leaders of all three parties met earlier and re-affirmed their commitment to completing negotiations in good faith.
They also said they are still working to conclude a draft programme for government by the end of the month.
It follows a row between Fine Gael and Fianna Fáil over election planning by the Department of Housing during the pandemic.
Fianna Fail TD for Galway West, Éamon Ó Cuív told The Hard Shoulder the discussions need to allow time for alternatives to be considered.
"The odds are on that they put some package together - will that pass the three parties?"
"A postal vote is what I understand is going to happen, and there's something like 18,000 members.
"There's a big membership, there'll be a big campaign.
"There'll be those who are for - obviously the leadership [and] most of the parliamentary party are for.
"But it seems to me there are quite a number of people who are members of the party who are not in favour of this particular arrangement.
"But it also depends on what's in the programme for government, and we have to see what's published."
"But what we have to make sure is there will be a deadline at some stage that will have to pass legislation, particularly to keep money flowing.
"We need, and they need, to build into their thought processes that they come to an end to these discussions at a time that allows you have the ratification arranged from within the party and still leaves enough time, if that fails, for other solutions to be looked at.
"There's no shortage of other alternatives - but there needs to be enough time before we run out of money to pay the bills, and there are limits in terms of law as to how much you can spend without passing further legislation".
"I think if this particular long, long process comes to an inconclusive [end] or a rejection, I think we all have to think it out again".
Asked if he would support a Fine Gael/Fianna Fáil coalition, he said: "We're jumping two steps ahead.
"If there's a programme for government put together, I think it's very unlikely I'll support it".
