President Michael D Higgins has warned that the United Nations and its agencies are under attack, as he defended the principle of multilateralism in a speech to the United Nations General Assembly.

“The international order is now again under grave pressure,” Mr Higgins said in his keynote address in New York on Wednesday evening. “The very idea of a rules-based order is being called into question and undermined. The international institutions - admittedly flawed and imperfect - which have been nurtured since 1945, and which have brought much benefit to our peoples, are the subject of questioning, withdrawal of support and even attack.”

Outlining Ireland’s commitment to the United Nations, he said that the organisation had anchored Ireland’s foreign policy, describing the UN as a “special institution where newly free nations found a home after their struggles for independence, their emergence from the shadows, legacies and distortions of imperialism.”

Mr Higgins also addressed the challenge of climate change. Noting it is “moving so much faster than the efforts we are expending or enlisting to address it,” he warned: “the cost of inaction is catastrophic.”

Mr Higgins’s speech was the centrepiece of his visit to New York this week, a key part of Ireland’s bid to secure a seat on the UN Security Council in 2021 and 2022.

Ireland’s experience in conflict resolution was also a theme of his address. The President noted in particular that the Israel-Palestine conflict “resonates deeply with the Irish people.”

“We have a deep sense, from our own experiences, of the centrality of national identity and a sense of belonging, and how this persists through decades and centuries,” he said, noting that peace processes needed to find a way for different identities and narratives to co-exist and no longer have to compete in a “zero-sum game.”

Earlier, the President said that he believed Ireland had a “good case to make” for securing a seat on the UN Security Council in 2021 and 2022.

Noting that much of the decision-making is made by the five big members of the security council, he noted that small countries have historically been able to effect change on the security council. Highlighting the fact that about 100 of the UN member states have populations the same or less than Ireland he said: “They are actually the ones who speak on issues like proliferation, cluster bombs, disarmament and climate change.”

Mr Higgins defended his own practices in relation to climate change, as well as those practiced in Áras an Uachtaráin, noting that he planned to travel by ship to Athens and Cyprus in October, while he regularly travels to Belfast by train.

In a speech at New York University on Tuesday evening he said that Ireland “believes profoundly” in the United Nations, highlighting how Ireland, like the United Nations itself, emerged from conditions of conflict. Ireland’s “long and painful” escape from a colonial past means that it can empathise with so many countries in the UN he said.