US President Donald Trump will bring his “America First” agenda to the UN for his first appearance at the General Assembly this week as the world grapples with the threat of an increasingly volatile North Korea.

All eyes will be on Mr Trump and new French President Emmanuel Macron as leaders and foreign ministers from more than 100 countries gather in New York for the summit.

Mr Trump, who once described the UN as “just a club for people to get together, talk and have a good time”, is expected to pursue his “America First” agenda at the General Assembly while also pushing for the more conventional goals of “peace” and “prosperity”.

“Sovereignty and accountability are the essential foundations of peace and prosperity,” the Trump administration’s national security adviser HR McMaster told reporters at the White House.

“America respects the sovereignty of other nations, expects other nations to do the same, and urges all governments to be accountable to their citizens.”

Foreign policy analysts say his appearance on the biggest stage in international diplomacy would be the first chance for a number of world leaders to take Mr Trump’s measure and to try get on his good side.

Given Mr Trump’s previous skepticism towards the UN, many nations are bracing for a harsh assessment of the organisation when Mr Trump addresses the General Assembly on Tuesday (US time).

The US has also shrunk its delegation for the summit compared to the team sent by the Obama administration, which analysts believe may allow other leaders such as Mr Macron to seize a more prominent leadership role.

Julie Bishop will represent Australia at the UN. Photo: AAP

Mr McMaster said Mr Trump would push a message of “reform”, saying that the UN “holds tremendous potential to realize its founding ideals, but only if it’s run more efficiently and effectively”.

Ahead of the summit, the White House was forced to deny reports it would backflip on a pledge to quit the Paris climate accord after a European diplomat said a Trump administration had reflected a possible softened stance on the issue.

The global gathering comes days after North Korea’s latest missile launch over Japan on Friday, which was strongly condemned by the United Nations Security Council.

The latest sanctions imposed against the regime have been described as the toughest yet, including a ban on the country’s textile exports and capping imports of crude oil. Despite this, Kim Jong-un has vowed to continue the country’s nuclear weapons program.

The campaign of violence has seen 400,000 Rohingya Muslims flee to Bangladesh in the past three weeks, with the UN Security Council last week condemning Myanmar for the first time in nine years.

Aung San Suu Kyi, who has been criticised for not speaking out against the violence, cancelled her visit to the UN amid the crisis.

Australia will be represented by Foreign Minister Julie Bishop as it seeks to gain a place on the UN Human Rights Council.

“Promoting Australia’s credentials to serve on the UN Human Rights Council in 2018-20 will be a priority,” she said.

Ms Bishop said she would also reiterate the need for the full implementation of recently agreed sanctions against North Korea and attend a Joint Investigation Team meeting into the downing of MH17.

The UN will also be expected to deal with the increased violence in Myanmar, which UN Secretary General Antonio Gomes all but described as ethnic cleansing last week.