UN Secretary-General Antonio Guterres said Wednesday he is hoping for a constructive message from US President Donald Trump when he makes his first address to world leaders at the United Nations next week.

Trump will speak at the UN General Assembly on Tuesday, taking to the podium of the global institution that he once disparaged as a "club" for "people to have a good time."

Guterres told a news conference ahead of the annual UN gathering that he had spared no effort to develop strong ties with the new US administration over the past eight months.

"All the efforts I have been making until now are in the direction of trying to create conditions for the relationship between the United States and the United Nations to be a constructive relationship," Guterres said.

"I hope that will also be the message of President Trump and I hope that if that is the message that will be conveyed, that that message will be well received."

Some 130 world leaders are attending this year's gathering, but the spotlight will be firmly on Trump.

The United States is the UN's number one financial contributor, paying 28.5 per cent of the $7.3 billion peacekeeping budget and 22 per cent of the core budget of $5.4 billion.

The Trump administration has threatened deep cuts to US funding to the world body, while US Ambassador Nikki Haley was a driving force behind a $600 million cut to the UN peacekeeping budget this year.

- Trump pushes UN reform -

Trump on Monday will host a meeting of world leaders on reforming the United Nations and to support Guterres' plan for a more effective UN response to global crises.

The US president has described the United Nations as an "underperformer" but stressed that it has "huge potential" to address the long list of world crises that will be at the center of this year's UN debate.

Guterres is due to meet Trump on the sidelines of the General Assembly debate for talks expected to focus on the North Korea crisis, the violence in Myanmar, Iran and climate change.

Asked about his message on the Iran nuclear deal that Trump has threatened to scrap, Guterres said it was a "very important" agreement and that "all parties should do everything possible for this agreement to be preserved."

Referring to "recent events" like Hurricane Irma that has battered parts of the United States, the UN chief said the Paris climate agreement should be implemented and that the new green economy could rescue the planet.

Trump announced in June that the United States was withdrawing from the agreement on curbing greenhouse gas emissions, but diplomats are hoping for signs of a shift when he addresses the assembly on Tuesday.

Guterres said that Trump's America-First policy was not in contradiction with a strong leadership role for the United States at the United Nations and in the world.

"It's my deep belief that the best way to preserve the American interests is to engage positively in global affairs and to engage positively in support of multilateral organisations like the UN," he said.

source: AFP