Natalie Geisenberger criticised conditions in Beijing after being forced into quarantine over a close contact case ©Getty Images

German Olympic champions Natalie Geisenberger and Felix Loch have expressed concerns over the implementation of COVID-19 measures at a Beijing 2022 test event, as preparations for the Winter Olympics continue.

Geisenberger, a four-time Olympic champion, was quarantined by organisers after initially being deemed to be a close contact of a passenger on a flight who tested positive.

The German luge star posted on Instagram they did not sit in the seats impacted, with suitcases having been stored in those places, and called on the International Luge Federation (FIL) to clarify the situation.

Her team-mates, Dajana Eitberger and Julia Taubitz, were also affected.

"We do not even find out the reason why we are treated like this and have to endure all of this," Geisenberger wrote, according to the German Press Agency.

"We are only allowed out of the room when there is track training, we do not get really decent food in plastic cups and bags in front of the door, we have no way of moving," she posted.

"Dear FIL, can you please give us the reasons."

Geisenberger later posted an update that she had been contacted by FIL President Einars Fogelis.

The official reportedly attempted to provide reassurance the organisation was working with the International Olympic Committee (IOC) to resolve the situation.

"I had a long, very pleasant phone call with Einars Fogelis, the President of the FIL, he was only able to help me or us to a limited extent at the moment, but he explained the situation and is in constant contact with the IOC and they try to resolve the situation for those affected," Geisenberger wrote.

"In some cases, this has even been achieved.

"The chairman of the German Bobsleigh, Luge, and Skeleton Federation (DSB), Thomas Schwab, also contacted me and told me that he was behind us and that he was trying everything to make the situation more bearable, but that he could not promise anything.

"In any case, there has been movement in the matter, so that gives us a little courage."

DSB President Schwab told Sportschau that daily extensions of quarantine periods were "not possible" as the federation sought clarification.

"I'm totally behind Natalie," Schwab said.

"In such an authoritarian system, everything is always a bit different, but we certainly won't muzzle our athletes."

Three-time Olympic champion Loch reportedly described the measures at the sliding centre in Yanqing and the hotel as "quite a challenge".

International teams featuring almost 250 people have been training at the Yanqing National Sliding Centre over the past week.

This followed a chartered flight from Frankfurt in Germany to Beijing.

The opening Luge World Cup of the season, doubling up as a test event, is scheduled to take place at the course from November 19 to 21.

Organisers confirmed last week two foreign luge athletes had tested positive during the test events.

China has among the strictest coronavirus prevention policies in the world.

Entry to the country is restricted, and almost everyone who does must quarantine in a hotel for at least two weeks, even if they are vaccinated and test negative.

The quarantine requirement is being waived for the test events and the Games, but participants must live and compete in isolation from the rest of the population in China, known as a "closed-loop" system.

Senior Chinese officials have reportedly urged strict implementation of COVID-19 rules, while the IOC has sought to reassure participants over close contact rules following several cases at the Tokyo 2020 Olympic Games.