China will build a "new model" of relations with the United States, President Xi Jinping said on Wednesday in a speech that portrayed China as the leader of a globalised world where only international cooperation could solve the big problems.

Two days before the inauguration of Donald Trump who has promised to be a U.S. president putting "America first", Xi urged countries to resist isolationism.

"Trade protectionism and self-isolation will benefit no one," Xi told an invited audience at the United Nations in Geneva.

"Big countries should treat smaller countries as equals instead of acting as a hegemony imposing their will on others."

Xi called for the world to unite on everything from environmental protection to terrorism and nuclear disarmament, in contrast to Trump who has said he has an "open mind" on climate change and that the United States would win any nuclear arms race.

"We will build a circle of friends across the whole world," Xi said.

"We will strive to build new model of major country relations with the United States, a comprehensive strategic partnership of coordination with Russia, a partnership for peace, growth, reform and among different civilizations and a partnership of unity and cooperation with BRICS countries."

While U.N. Secretary-General Antonio Guterres told Xi it was "very reassuring to see China assuming such a clear leadership in multilateralism in today's world", rights campaigners expressed concerns about China's record.

“It is unfortunate that Chinese President Xi was given an obsequious red carpet treatment at the U.N. today while NGOs with concerns about his dismal rights record were kept out," said Sophie Richardson, China director at Human Rights Watch.

Western governments have accused China of widespread rights abuses and its smaller neighbours say it has expansionist ambitions in the South China Sea, things Beijing denies.

"We always put people's rights and interests above everything else and we have worked hard to develop and uphold human rights," Xi said. "China will never seek expansion, hegemony or sphere of influence."

Xi's speech was the finale of a trip that included topping the bill at the World Economic Forum in Davos. The United Nations - at risk of budget cuts from Trump - ensured the grandest possible welcome for Xi, and many U.N. staff went home early to clear the way for the red carpet.

Trump tweeted on Dec. 26 that the United Nations "has such great potential but right now it is just a club for people to get together, talk and have a good time. So sad!"