Taoiseach Leo Varadkar has said Sinn Fein and the DUP are no longer close to a deal to restore power-sharing at Stormont.
The Taoiseach admitted that hopes which surfaced last week of an imminent agreement had now dwindled.
He said the "big things" were not being dealt with in Northern Ireland because the two main parties were "arguing about the intricacies of an Irish Language Act".
On the reasons for the lack of progress, he said: "I will let the different parties account for themselves as to what went wrong."
Mr Varadkar was speaking during a visit to areas in Co Kildare hit by Storm Ophelia.
When asked about the chances of a political breakthrough at Stormont, he said: "At the moment they're not close to a deal.
"Things did look encouraging at the start of last week and became less favourable during the week."
Mr Varadkar listed the pressing problems Northern Ireland faced in the absence of a functioning government.
"There are big things to deal with," he said.
"Brexit could have a huge impact on Northern Ireland. Their public services are about to run out of money because the budget allocation is running out.
"They have big challenges in their health service and ... they are facing some very severe water damage and, meanwhile, both the DUP and Sinn Fein are arguing about the intricacies of an Irish Language Act.
"It would seem to me that what the people of Northern Ireland want is for their politicians to get together and start looking after the business of Northern Ireland and making sure Northern Ireland has a unique voice in these negotiations on Brexit."
Meanwhile, Sinn Fein has criticised the Taoiseach over his remarks regarding Irish unity in an interview with BBC's Spotlight last night.
"I wouldn't like us to get to the point whereby we are changing the constitutional position here in Northern Ireland on a 50% plus one basis," Mr Varadkar said.
"One of the best things about the Good Friday Agreement is that it did get very strong cross border support - that's why there was a 70% for it.
"I don't think that there would be a 70% vote for a united Ireland in the morning, for example, or anything remotely close to that.
"And I really think we should focus on making the agreement that we have work." In response, Sinn Fein MLA Conor Murphy said the overwhelming majority of people in Ireland supported Irish unity.
"The Irish government should reflect that and defend the Good Friday Agreement in all its parts, including the right of a majority to vote for a united Ireland," he added.
"The Good Friday Agreement is absolutely clear in enshrining the right of the Irish people to self-determination through referenda, north and south.
"If a simple majority vote in favour of reunification, both governments are then obliged to legislate for it. The Good Friday Agreement is the legal and internationally-biding position."
Mr Murphy said there was "an onus" on Dublin "to plan for unity, to become a persuader for unity, to build the maximum agreement and to secure and win a referendum on unity".
As a "co-guarantor of the Good Friday Agreement, the Taoiseach should be "seeking to defend the agreement in all its parts, not seeking to undermine it," he added. SDLP leader Colum Eastwood urged the Taoiseach to stick to what was decided by politicians in the 1998 Good Friday Agreement.
"While the SDLP continue to work as persuaders for unity and want to see the largest possible endorsement across the island, the Good Friday Agreement provides that a simple majority is the mechanism," he said.
"It would be unwise to attempt to re-negotiate the principle of consent at the heart of the Good Friday Agreement.
"It is what the Irish people, North and South, signed up to in 1998."
In a wide-ranging interview with Spotlight, Mr Varadkar also spoke candidly about Brexit, his decision to come out as a gay man, and his family's role in the struggle for independence in India.