Spectators have been captured flouting Tennis Australia's new ban on Russian and Belarusian flags being displayed at the Australian Open.
TA had initially permitted spectators to bring Russian and Belarusian banners to Melbourne Park, as long as they did not cause disruption.
But the policy was reversed on Tuesday morning after a Russian flag was prominently displayed courtside during a match involving Ukrainian player Kateryna Baindl.
Just hours after the ban was implemented, a Russian flag was hoisted by fans during the match between Russian fifth seed Andrey Rublev and Austrian Dominic Thiem on John Cain Arena.
"A banned flag was waved by spectators during a match at JCA on Tuesday," a TA spokesperson told AAP.
"The patrons were spoken to by security and the flag was removed."
The appearance of a Russian flag during Baindl's three-set match against Russian Kamilla Rakhimova on Monday drew condemnation on social media from Ukraine's ambassador to Australia Vasyl Myroshnychenko.
Russian and Belarusian players are allowed to compete at the first grand slam tournament of 2023, but must do so under a neutral banner.
They were banned by the All England club from participating at Wimbledon last year in reaction to Russia's ongoing invasion of Ukraine.
Russia is Belarus' largest and most important economic and political partner.
"Flags from Russia and Belarus are banned onsite at the Australian Open," TA said in a statement.
"Our initial policy was that fans could bring them in but could not use them to cause disruption.
"Yesterday we had an incident where a flag was placed courtside.
"The ban will be effective immediately.
"We will continue to work with the players and our fans to ensure that this is the best possible environment to enjoy the tennis."
Belarusian star Aryna Sabalenka, who is the highest-ranked Russian or Belarusian player in the women's draw, said she had "zero control" over the flag situation.
"I really thought that sport is nothing to do with politics," the fifth seed said after her first-round demolition of Czech Tereza Martincova on Tuesday.
"But if everyone feels better this way, then it's OK. No flags, no flags OK.
"I'm pretty sure they (Ukrainians are) upset about that, and if Tennis Australia made this decision to make them feel better, they did it, I mean, what can I do. I can do nothing."