The Australian Open reversed a policy that banned fans from wearing a shirt that says, "Where is Peng Shuai?"
The Chinese tennis player accused a former government official of sexual assault last year on social media. She has made few public appearances since making the accusations.
The WTA issued a statement in December that said there are concerns about whether Peng is free and safe.
During the Australian Open, fans were reportedly told to cover their "Where is Peng Shuai?" shirts after protesting.
Tennis Australia has a policy that bans "banners, signs or clothing that are commercial or political."
Facing backlash, however, Tennis Australia CEO Craig Tiley told Agence France-Presse (AFP) that fans could wear the shirts.
"As long as they are not coming as a mob to be disruptive but are peaceful," he said.
The Australian Open is the first grand slam tennis tournament of the year.
It wraps up on Jan. 30.