United Nations Secretary General Antonio Guterres defended his organisation's support for the Olympic Games on Saturday, saying it was important for nations to come together in Beijing as conflicts brew across the world.

Following a meeting with International Olympic Committee (IOC) President Thomas Bach a day after the official opening of the Beijing Winter Games, Guterres said the Games' message of solidarity was important.

"When we see so many conflicts around the world, we see the absolute relevance of having Olympic Games in which all countries are represented -- even, unfortunately, some that are in a war situation.

"To have them all here and to show that peace is possible, that unity is possible, and that solidarity is possible; this fully justifies the strong commitment of the United Nations to support the International Olympic Committee."

The IOC has been criticised for years after awarding the Games to China back in 2015 with some nations, including the United States and Britain, deciding on a diplomatic boycott of the Games in Beijing over the country's human rights record.

The Olympics are also held under the shadow of a potential military conflict between Russia and Ukraine as well as heightened tensions between China and Taiwan.

Russia has amassed 100,000 troops near its border with Ukraine as it tries to pressure the country into ruling out future NATO membership.

"I think we need at this moment more than ever the message of unity and solidarity that is the message of the Olympic Games," Guterres said.

"In a moment when we see so many expressions of populism, so many expressions of racism, so many expressions of xenophobia, anti-Semitism, anti-Muslim hatred, to be here and to be with athletes that come from all cultures, from all countries, from all ethnicities, from all religions, it's a fantastic message," Guterres said.

The Games run until Feb 20.