LOS ANGELES: The Women's Tennis Association (WTA) is still trying to make "direct contact" with Chinese tennis star Peng Shuai, who has not been seen or heard from publicly since she accused former vice-premier Zhang Gaoli of coercing her into sex.

Concern among the global tennis community and beyond has grown over Peng's safety and whereabouts since her allegation, with the WTA calling for an investigation.

"We continue all of our efforts to reach out and hopefully speak to her directly," WTA CEO Steve Simon said in an interview with Tennis Channel on Friday.

Former doubles world number one Peng said on Chinese social media on Nov. 2 that Gaoli coerced her into sex and they later had an on-off consensual relationship.

Simon, who told CNN and other U.S. media outlets on Thursday that the tour would consider pulling tournaments worth tens of millions of dollars from China, called the situation "a significant issue."

"Where we're at right now is we want to make sure that Peng Shuai is first of all safe, Simon said.

"We have received assurances from the Chinese Tennis Association that she is safe and not in harm's way, but we haven't been able to speak with her directly and we haven't been able to reflect to her directly our concerns or reflect to her all of the support that's available to her."