Czech Renata Voracova has become the second Australian Open participant detained in a sweep by authorities on players entering the country with vaccination exemptions.
Doubles specialist Voracova's detention follows that of world No.1 Novak Djokovic, who was detained at Melbourne Airport on Wednesday.
Voracova played in Melbourne earlier this week, but local media reports she has been asked to leave Australia, after her detention by Border Force officials.
The Czech Foreign Ministry says Voracova decided to leave the country.
The Australian Border Force (ABF) says an individual has left the country voluntarily, while a third had been taken into immigration detention, without naming the Czech player.
"The ABF can confirm that one individual has voluntarily departed Australia, following ABF inquiries.
"We can also confirm that the visa of a third individual has been cancelled. This person has been taken into immigration detention pending their removal from Australia."
The Czech Foreign Ministry adds it has formally protested through its embassy in Canberra.
Voracova was a promising junior, who won the French Open girls doubles title in 2001.
The 38-year-old made her Grand Slam singles debut in 2002 at New York, but has won only one of her 12 matches at the majors and is currently ranked 81.
She has fared far better in doubles, winning 11 titles and reaching the Wimbledon semi-finals in 2017. Voracova has career earnings of US$1.88 million.
She is being held at the Park Hotel in Carlton - the same hotel where Djokovic, who has won US$154.7 million in prizemoney, along with 20 Grand Slam titles, is detained.
In another development, the Herald Sun published information sent from Tennis Australia to players on December 7 that shows it passed on advice on grounds for medical exemptions that differs from the recommendations it received from federal authorities.
The document advises a COVID-19 infection in the last six months could be considered grounds that would enable an unvaccinated player to enter the country, provided it was accompanied by documents certifying the infection.
That contradicts advice the Federal Government sent to TA in November, stressing that a prior infection in the past six months did not meet the requirements for quarantine-free entry.
The Victorian Government says TA did not advise them of this development.
TA told the Herald Sun it completely rejected that players were "knowingly misled" and had used guidance from the Health Minister's advisory group on immunisation to explain player eligibility under Victoria's laws to the playing group.
Meanwhile, Djokovic has posted on social media, thanking his fans for their support, as he tries to stall his deportation.
"Thank you to people around the world for your continuous support," the Serb says on Instagram. "I can feel it and it is greatly appreciated."