Simon Harris has pledged to honour his role as a protector of the Good Friday Agreement as he stressed that peace on the island of Ireland should never be taken for granted.

The new Taoiseach said he looked forward to working with counterparts in the Northern Ireland Executive.

In one of his last engagements as higher education minister, Mr Harris joined colleagues from the Irish cabinet and Stormont ministers at a meeting of the North South Ministerial Council in Armagh on Monday.

He referenced the gathering in his address to the Dail on Tuesday after being nominated as Ireland’s new premier.

“As Taoiseach, I pledge to guard and honour my role as protector and guarantor of the Good Friday Agreement,” he added.

“We have so much more to achieve for all communities on this island, and I look forward to working very much with the Northern Ireland Executive because Ireland must never take peace or freedom for granted.”

The new Fine Gael leader has said the reunification of Ireland should not be a priority at the present time.

However, he has insisted he remains committed to the objective and hopes he will see it achieved in his lifetime.

Mr Harris has also said costing should not be the overbearing factor in consideration of a united Ireland.

On Sunday, he was asked about the findings of a new study from the Dublin-based Institute of International and European Affairs (IIEA) that suggested unification could cost the Irish government 20 billion euros a year for 20 years, with a 25% increase in taxation potentially needed to shoulder the costs of uniting Northern Ireland and the Republic of Ireland.

“Instinctively, I want to see a united Ireland and cost isn’t the overbearing factor,” Mr Harris told RTE in response to the report’s findings.

But he stressed his priority was harnessing the “full potential” of the Good Friday Agreement and building better cross-border relations.

Mr Harris said he would not be dismissive of the IIEA report but said its findings had prompted a lot of scrutiny.

“There’s a dynamic effect to any economic change, but the point is the Good Friday Agreement provides a way forward for people’s political aspirations,” he told RTE’s The Week In Politics show.

“The priority right now, in my view, for the people on the island of Ireland is to live in peace, live in prosperity, get to know each other better, cooperate and collaborate.”