A Border poll on a united Ireland would be "defeated and divisive" and would not be a good idea, Taoiseach Leo Varadkar has warned.
He said neither unionists nor parties supporting a united Ireland currently have a majority.
Commitment to the Belfast Agreement, power-sharing in the North and cross-Border co-operation “all in a wider east-west context” is what is needed now, he said.
They need to try and heal some of the divisions and tensions that exist in the North “and among us all”.
When the Assembly and Executive are up and running properly, that is the time “to have a long look and a long hard look at the institutional arrangements and the constitutional arrangements”.
Speaking to the media at his annual Christmas press conference, Mr Varadkar ruled out a Border poll.
He said there had been change in the past four elections – the Westminster general election, the European and local elections and the previous Westminster election in 2017.
“For the first time since the foundation of Northern Ireland, unionist parties do not have a majority any more,” he said.
“It wasn’t a one-off – it’s four elections now, of different sorts. But also, parties that support a united Ireland don’t have a majority either.
“It’s still in and around 40 per cent and that is far short of the 50 per cent plus one you would need to win a Border poll and that’s why I don’t think a Border poll is a good idea. It would be defeated and divisive. I don’t see who would gain from that sort of scenario.”
Mr Varadkar noted a “growing middle-ground, more people willing to vote for Alliance and Greens and PBP (People Before Profit) and other non-sectarian parties, if you like, particularly around the Belfast area, and that’s a significant development too”.
But he stressed that in looking at constitutional arrangements it was “important to do that right”.
He said it should be done in the context where the Assembly and Executive were up and running and where the Belfast Agreement was “functioning as it was intended and then see whether there’s a time for a change or reforms on foot of that”.
Asked about the prospect of a Citizens’ Assembly, Mr Varadkar reiterated his view that any forum or assembly that did not involve “at least some decent section of unionist opinion wouldn’t be the right approach”.
“We have to learn from our history and we have to understand that there are a million people on this island who are British and are unionists and we need to respect that and make sure that they are part of the future and that they are accommodated and that they feel part of the future.”
Mr Varadkar also supported the idea of a bridge between Northern Ireland and Scotland but insisted that the UK would have to pay for it. He said there should be a “high-level engineering assessment as to whether it is a viable proposal”.
But the Taoiseach said that when he told the British prime minister he expected the UK to pay for the 30km bridge, Boris Johnson replied: "No, no the EU is going to pay for it".
“So that’s definitely not going to happen, because neither Northern Ireland or Scotland are going to be in the EU.”