The tennis player at the centre of sexual assault allegations against a Chinese government official has not been heard from since airing her claims, sparking a response from a world tennis body and widespread concern from players about her safety. 

After over a week of silence on the issue, the head of the women's professional tennis tour has called for a full investigation of sexual assault allegations made by two-time Grand Slam doubles champion Peng Shuai, from China. 

Earlier this month, Shuai, a former No. 1-ranked doubles player, wrote in a lengthy social media post that Zhang Gaoli, a former vice premier and member of the ruling Communist Party's all-powerful Politburo Standing Committee, had forced her to have sex despite repeated refusals following a round of tennis three years ago. 

Her post — which was removed from her verified account on Wiebo, a leading Chinese social media platform — also said they had sex once seven years ago and she had feelings for him after that. 

"The recent events in China concerning a WTA player, Peng Shuai, are of deep concern," WTA Chairman and CEO Steve Simon said in a statement released by the tour on Monday. 

"In all societies, the behaviour she alleges that took place needs to be investigated, not condoned or ignored. We commend Peng Shuai for her remarkable courage and strength in coming forward. Women around the world are finding their voices so injustices can be corrected. 

"We expect this issue to be handled properly, meaning the allegations must be investigated fully, fairly, transparently and without censorship," Simon said. 

Shuai's initial post and the WTA's long silence sparked considerable criticism and concern amongst the tennis world, with fans and players using the hashtag #WhereIsPengShuai to try to raise awareness for her cause. 

"Yes, these accusations are very disturbing," tweeted 18-time Grand Slam winner Chris Evert on Monday. "I've known Peng since she was 14; we should all be concerned; this is serious; where is she? Is she safe? Any information would be appreciated." 

The hashtag was also used on Sunday by French player Alize Cornet who said "let's not remain silent" and British Davis Cup player Liam Broady who wrote on Sunday: "I can't believe that this is even happening in the 21st century." 

"The fact that Peng Shuai is missing is not only the WTA's problem. We are all concerned," tweeted another French player, Nicolas Mahut, on Monday after the statement was released. 

Peng has won 23 tour-level doubles titles, including at Wimbledon in 2013 and the French Open in 2014. She was a semifinalist in singles at the US Open in 2014, achieving the same result in the 2011 edition of Auckland's ASB Classic. 

Her accusation was the first against a prominent government official since the #MeToo movement took hold in China in 2018 before being largely tamped down by authorities the same year. 

In the post, Peng, 35, wrote that Zhang, now 75, and his wife arranged to play tennis in Beijing about three years ago and that he later brought her into a room at his home where the assault occurred. 

"I was so frightened that afternoon, never thinking that this thing could happen," the post said. 

Zhang retired in 2018 and has largely disappeared from public life, as is usual with former Chinese officials. 

There have been no public statements from Peng since her initial post and also no public response from Zhang. 

- with AP