Government formation talks between Fianna Fáil, Fine Gael and the Green Party focused this evening on the controversial question of agriculture and reducing greenhouse gas emissions.
It is understood there were some difficulties over the impact on agriculture of any plan to reduce emissions by 7% each year.
The talks will resume in the morning with slow and steady progress reported at the close of business tonight.
If there is to be an agreed programme for government, then a deal will have to be secured on the Green Party's demand for a 7% annual reduction in emissions.
Fianna Fáil and Fine Gael negotiators have made it clear that, from their perspective, neither Irish agriculture, nor rural Ireland, can take a big hit to realise that aim.
In the Dáil this afternoon, Green Party leader Eamon Ryan denied claims that his party in government would be bad for the rural economy.
He said: "People are very worried. People are presenting all sorts of scare stories that the Greens are going to be bad for rural Ireland, bad for farming, bad for beef, bad for dairy. I fundamentally disagree."
Yesterday's talks on the topic between the parties were described as "useful".
However, a speedy resolution to this logjam needs to be found, given an overall deal is supposed to be concluded on Friday or, at the latest, by the weekend.
Another difficulty facing the negotiating teams is the large volume of text that still needs to be signed-off by negotiators sitting in plenary session.
The three party leaders can be expected to play an increasingly prominent role, as the more intractable problems are kicked upstairs for a final decision.
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Separately, responding to reports that there may not be a Minister for Children and Youth Affairs in the next government, Katherine Zappone said that if this were to happen "it would be an exceedingly regressive move".
She said she did not think it would "fit well with a programme for government that purports to offer a new vision for Ireland's recovery, from the negative impact of this (Covid-19) pandemic especially for children and families".
She said: "To eradicate this role I think would bring Ireland back to an era where children are seen and not heard."
Reporting Micheál Lehane and Paul Cunningham