The Women's Tennis Association (WTA) has opened an investigation into Peng Shuai's sexual assault allegations against a former China leader.

Shuai, 35, posted on Chinese social media site Weibo allegations against Zhang Gaoli – the ex-vice premier and member of the Chinese Communist Party's Politburo Standing Committee – claiming he had forced her to have sexual relations with him.

In the post, published on Tuesday before subsequently being deleted, the 2013 Wimbledon doubles champion alleged that the pair had extramarital relations and she had developed feelings for him.

All of Peng's content has since been removed from Weibo and numerous reports suggest she has not been seen in recent days.

The WTA's chairman Steve Simon addressed the matter on Sunday in a statement that said: "The recent events in China concerning a WTA player, Peng Shuai, are of deep concern. As an organisation dedicated to women, we remain committed to the principles we were founded on – equality, opportunity and respect.

"Peng Shuai, and all women, deserve to be heard, not censored. Her accusation about the conduct of a former Chinese leader involving a sexual assault must be treated with the utmost seriousness.

"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.

"Our absolute and unwavering priority is the health and safety of our players. We are speaking out so justice can be done."