According to the Chinese state-run Global Times, the system which designed to guard against spreading COVID-19 started operating today with exactly a month to go before the Winter Olympics are due to open on February 4.

It comes into use as overseas Beijing 2022 workers start to arrive in the Chinese capital to prepare for the Games.

Those who are fully vaccinated do not need to self-isolate for 2021 days before entering the closed loop. 

Once within the Olympic bubble, people will undergo daily testing for COVID-19 and will be unable to access the outside world for the duration of their time in Beijing.

High-speed trains will be made available within the system, but Games personnel will be in separate carriages from the public to mitigate the risk of spreading COVID-19.

The designated transport will be used to move between approved locations, including competition and training venues and the Olympic Village.

The closed-loop system - which will apply to all three Olympic zones in in Beijing, Zhangjiakou and Yanqing - is central to organisers' COVID-19 countermeasures.

Those who are fully vaccinated will not need to isolate for 21 days before entering the closed loop.

Zhao Chengfang, a deputy head of the COVID-19 prevention department at the Capital Gymnasium - the venue for figure skating and short track speed skating competitions – told the Global Times that the system was now in use.

"Event support staff from overseas will arrive at the venues to begin their work from Tuesday," said Zhao.

"Venues will also begin to strictly enforce the same vaccination policies as those in place for the Games.

"Local Olympic-related personnel will also enter the closed loop."

Shougang Park, which will stage the big air events at Beijing 2022, reportedly joined the closed-loop system on Saturday (January 1), while the Main Media Centre based at the China National Convention Center entered today.

Thousands of athletes, officials, volunteers and journalists are due to arrive in Beijing over the coming weeks.

Overseas spectators have been banned because of the pandemic, but organisers hope to have domestic fans in attendance.

The rapid spread of the highly contagious Omicron variant has raised question marks over the staging of the Winter Olympics as countries impose tougher restrictions.

But Wang Wenbin, a spokesperson for the Chinese Foreign Ministry, has reiterated the host nation's confidence in hosting a safe event next month.

"We are confident that we will be able to overcome the challenges associated with the proliferation of omicron and will present the world with a safe, brilliant Olympics," said Wang.

Under its "zero-COVID" policy, China has had what are among the world's strictest coronavirus prevention measures.

Wang claimed the host nation had established a "highly-effective system" to battle coronavirus and insisted it would "ensure the safety and comfort of the athletes who arrive at the Games".

The pandemic has been one of the defining topics of the build-up to Beijing 2022, along with China's record on human rights and a United States-led diplomatic boycott on such grounds.

The National Hockey League is no longer releasing its players - considered the best men's ice hockey athletes in the world - for Beijing 2022, because of COVID-19 disruption.

The Beijing 2022 Winter Olympics are set to take place from February 4 to 20, with the Winter Paralympics following from March 4 to 13.