China's President Xi Jinping held his first face-to-face talks with a world leader in nearly two years on Friday, meeting Russia's Vladimir Putin who hailed "unprecedented" ties between the neighbours as tensions grow with the West.

Xi has not left China since January 2020, when the country was grappling with its initial Covid-19 outbreak and locked down the central city of Wuhan where the virus was first detected.

He is now embarking on a sudden flurry of diplomatic activity as more than 20 world leaders fly in for the Winter Olympics, an event China hopes will be a soft-power triumph and a shift away from a build-up blighted by a diplomatic boycott and Covid fears.

The two leaders met in the Chinese capital as their countries seek to deepen relations in the face of increasing criticism from the West.

Xi said he believed the meeting would "inject more vitality into China-Russia relations," according to CCTV.

A document agreed by the countries said they "oppose the further expansion of NATO" and called for the US-led defence bloc to abandon "Cold War era" approaches, the Kremlin said in a briefing afterwards.

Moscow is looking for support after its deployment of 100,000 troops near its border with Ukraine prompted Western nations to warn of an invasion and threaten "severe consequences" in response to any Russian attack.

Putin and Xi also criticised Washington's "negative impact on peace and stability" in the Asia-Pacific region, according to the Kremlin.

In televised remarks at the start of their meeting, Putin described Russia and China as an "example of a dignified relationship".

Russia has also prepared a new contract for the supply of 10 billion cubic metres of natural gas to China from Russia's Far East, Putin said.

The two leaders will attend the Olympic opening ceremony on Friday evening.

A virtual meeting between Chinese President Xi Jinping and Russian President Vladimir Putin, in shown on a screen in Beijing on December 15, 2021
A virtual meeting between Chinese President Xi Jinping and Russian President Vladimir Putin, in shown on a screen in Beijing on December 15, 2021 AFP / JADE GAO

While Russian officials are banned from attending international sporting competitions over a doping scandal, they may attend if invited by the head of state of the host country.

Spiralling tensions with the West have bolstered ties between the world's largest nation and its most populous, and Putin was the first foreign leader to confirm his presence at the Olympics.

"I have known President Xi Jinping for a long time," CCTV quoted Putin as saying in a report on Friday.

"As good friends and politicians who share many common views on solving world problems, we have always maintained close communication."

China's state-run Xinhua news agency also carried an article from Putin on Thursday in which the Russian leader painted a portrait of two neighbours with increasingly shared global goals.

He also hit out at the US-led Western diplomatic boycott of the Olympics that was sparked by China's human rights record.

"Sadly, attempts by a number of countries to politicise sports for their selfish interests have recently intensified," Putin wrote, calling such moves "fundamentally wrong".

China enjoyed plentiful support from the Soviet Union -- the precursor to the modern Russian state -- after the establishment of Communist rule in 1949, but the two socialist powers later fell out over ideological differences.

Relations got back on track as the Cold War ended in the 1990s, and the pair have pursued a strategic partnership in recent years that has seen them work closely on trade, military and geopolitical issues.

Those bonds have strengthened further during the Xi era, at a time when Russia and China find themselves increasingly at odds with Western powers.

Other leaders set to enjoy Xi's hospitality during the Games include Egypt's Abdel Fattah al-Sisi, Saudi Arabia's Mohammed bin Salman, Kazakhstan's Kassym-Jomart Tokayev and Poland's Andrzej Duda.

Around 21 world leaders are expected to attend the Games.

A majority of those leaders rule over non-democratic regimes, according to the Economist Intelligence Unit's Democracy Index.