After the Ukrainian ambassador urged action after the flags were spotted in the crowd on Tuesday, Tennis Australia banned the Russian and Belarusian flags from the Australian Open.
The prohibition was referred to as “unacceptable politicization of sports” by Moscow.
Fans waved the red, white, and blue flags of Russia during the first-round match between Russia’s Kamilla Rakhimova and Ukraine’s Kateryna Baindl on Monday.
Police and security were allegedly summoned to the stadium by Ukrainian supporters.
On Rod Laver Arena, a Russian flag was also flown during Daniil Medvedev’s match against American Marcos Giron.
“Flags from Russia and Belarus are banned onsite at the Australian Open,” Tennis Australia 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 is effective immediately. We will continue to work with the players and our fans to ensure the best possible environment to enjoy the tennis.”
Russian and Belarusian athletes have typically participated as independents under a neutral white flag since Russia’s invasion of Ukraine, as is the case in the Australian Open.
Vasyl Myroshnychenko, the ambassador of Ukraine to Australia and New Zealand, had contacted Tennis Australia late on Monday to request action.
“I strongly condemn the public display of the Russian flag during the game of the Ukrainian tennis player Kateryna Baindl at the Australian Open,” he tweeted.
“I call on Tennis Australia to immediately enforce its ‘neutral flag’ policy.”
Last week, the ambassador requested the Australian Open to completely prohibit players from Russia and Belarus, the latter because Belarus supports Vladimir Putin.
As a result of Wimbledon’s decision to exclude players from both nations last year, the ATP and WTA stripped the competition of its ranking points.
Doug Trappett, a former Australian ambassador to Ukraine who held the position from 2015 to 2016, criticized Australian Open organizers prior to the flag ban.
Writing on Twitter, he called it “embarrassing”.
“You could have banned Russian players and positioned yourself to give a robust response to such predictable incidents but you chose spinelessness,” he tweeted.