Duda was to appear alongside the leadership of the US-based Heritage Foundation, a conservative think tank close to US President Donald Trump's circle, which he joined in January as a "distinguished visiting fellow," his office director, Małgorzata Paprocka, told Polish state news agency PAP.
His address was expected to focus on "the value of a sovereign nation state and the Three Seas Initiative as a forum for cooperation of such states in Europe," she said.
He was also listed for a plenary session titled "The Significance of October 7" with Israeli Diaspora Affairs Minister Amichai Chikli.
The session fell on the third anniversary of the Hamas attack on southern Israel, which killed more than 1,200 Israelis. Israel's military campaign in Gaza since then has killed more than 75,000 Palestinians.
A UN commission of inquiry concluded last year that Israel had committed genocide in Gaza. Amnesty International, Human Rights Watch, the Israeli group B'Tselem and the International Association of Genocide Scholars have reached similar conclusions.
Israel rejects the allegation.
The National Conservatism (NatCon) gathering runs from Tuesday to Thursday.
It is organised by the Edmund Burke Foundation, a US think tank founded in 2019 and led by Israeli philosopher Yoram Hazony, which has previously held conferences in the United States and Europe.
Past participants include US Vice President JD Vance, Italian Prime Minister Giorgia Meloni, former Hungarian Prime Minister Viktor Orban and British pro-Brexit politician Nigel Farage.
The Guardian newspaper described this year's event as among the most significant recent gatherings of Israeli nationalists, American Christian nationalists and European far-right figures.
Israeli broadcaster Channel 14 said it brings together key figures in a movement seeking an ideological alternative to liberalism.
Speakers include Israeli Finance Minister Bezalel Smotrich, who was sanctioned last year by Britain, Australia, Canada, New Zealand and Norway for inciting violence against Palestinians.
Harald Vilimsky of Austria's far-right FPO party, with roots among former Nazis, is also on the programme. Israeli Prime Minister Benjamin Netanyahu met with him in January.
(jh/gs)
Source: PAP