Irish premier Enda Kenny has told Theresa May the outworking of the General Election must not put the Good Friday Agreement at risk.
The Taoiseach’s intervention comes amid concerns about the impact on the peace process of any DUP/Conservative link-up.
The 1998 peace accord, which provides the template for powersharing at Stormont, commits the UK and Irish governments to demonstrate “rigorous impartiality” when it comes to the differing political traditions in Northern Ireland.
The Conservatives’ ability to adhere to such a commitment if they are wedded to a parliamentary alliance with the DUP has been questioned.
The issue is particularly relevant at the moment, as talks to save the crisis-hit powersharing institutions at Stormont are due to resume on Monday.
Mr Kenny, who will formally retire as Taoiseach in the coming days to be replaced by new Fine Gael leader Leo Varadkar, said he spoke with Mrs May about protecting the Good Friday Agreement.
Earlier, Irish Foreign Minister Charlie Flanagan said a DUP/Tory agreement would “not necessarily” undermine the Northern Ireland peace process.
Charlie Flanagan said he has raised the matter with Northern Ireland Secretary James Brokenshire.
Mr Flanagan was asked about suggestions that any Conservative deal with the DUP would undermine Westminster’s impartiality as a co-guarantor of the Good Friday Agreement, also known as the Belfast Agreement.
He told ITV’s Peston on Sunday: “Well, not necessarily the case. Of course, it remains to be seen what the nature of that deal is.
“But this is an issue I did address the evening before last with Secretary of State James Brokenshire.
“I look forward to meeting with him again tomorrow if his appointment is reaffirmed, but yes I think it’s an important issue that you raise – the objectivity of both governments, and both governments working strictly in accordance with our legal responsibilities under the Belfast Agreement, the Irish government as co-guarantor, indeed the British Government as co-guarantor.”
A No10 spokeswoman said: “Prime Minister Theresa May spoke on the phone to Taoiseach Enda Kenny today. The Prime Minister explained that she is working towards a confidence and supply deal with the DUP which would provide stability and certainty for the UK going forward.
“They confirmed their joint commitment to restoring a Northern Ireland Executive as soon as possible and agreed that both countries would continue to engage closely to bring about political stability in Northern Ireland. The Prime Minister reiterated that the Government’s approach and objectives in the forthcoming talks to re-establish the Northern Ireland Executive remained unchanged.
“The two leaders spoke about their willingness to continue close cooperation as the UK embarks on leaving the European Union, with no return to a hard border.
“The Prime Minister thanked Mr Kenny for helping to make UK-Ireland relations stronger than ever, wished him well for the future and said she looked forward to continuing a close relationship with his successor.”