Ukraine's ambassador to Australia has called for Novak Djokovic's father to be banned from the Australian Open, after he posed with a group holding the Russian flag.
Footage shared to YouTube showed Srdjan Djokovic outside Melbourne Park standing with a group displaying a Russian flag superimposed with Vladimir Putin's face.
The incident took place at Melbourne Park on Wednesday night following Novak Djokovic's quarterfinal win over Russian Andrey Rublev.
One of the men in the video was wearing a T-shirt with the symbol "Z" — an emblem representing support for Russia's invasion of Ukraine.
Russian and Belarusian flags were banned from the tournament after a Russian flag was waved during the opening round.
The YouTube video was posted by a user identified as Simeon Boikov.
NSW Police has confirmed it is seeking Boikov's arrest on an unrelated matter.
Incident 'a disgrace for the tournament', ambassador says
Ukrainian ambassador Vasyl Myroshnychenko said the flag was a symbol of the invasion of Ukraine, and called on Tennis Australia to ban Srdjan Djokovic for the remainder of the tournament.
"It's unacceptable, it's a disgrace for the tournament," he said.
"There must be sanctions imposed."
He said Novak Djokovic needed to clarify his own position.
"It's important to ask Novak Djokovic his opinion on the situation," Mr Myroshnychenko said.
"Is he supporting Putin? Is he supporting war in Ukraine? What does he think about his father's support?"
Novak Djokovic's management was contacted for comment.
In March last year, Novak Djokovic pledged financial support to Ukrainian tennis player Sergiy Stakhovsky, who had joined the fight to protect his country from the Russian invasion.
"Thinking of you … hope all calms down soon," Novak Djokovic said at the time.
"Please let me know what would be the best address to send help. Financial help, any other help as well."
Opposition leader calls incident 'bizarre'
In a statement, Tennis Australia did not directly address the incident involving Srdjan Djokovic, but said some spectators were removed from Melbourne Park on Wednesday night.
"A small group of people displayed inappropriate flags and symbols and threatened security guards following a match on Wednesday night and were evicted," the statement read.
"Players and their teams have been briefed and reminded of the event policy regarding flags and symbols and to avoid any situation that has the potential to disrupt.
"We continue to work closely with event security and law enforcement agencies."
When asked about the incident, Prime Minister Anthony Albanese reiterated Australia's support for Ukraine.
"Australia stands with the people of Ukraine," he said.
"We don't want to see any support given to the Russian invasion of Ukraine that is having a devastating impact on the people of Ukraine."
Federal Opposition Leader Peter Dutton called the incident "bizarre".
"The Russian onslaught continues, and frankly everybody of goodwill should be trying to deter, not encourage, President Putin. So, it's a bizarre act," he told Channel 9.
"It's an issue for Tennis Australia as to how they react."
Victorian minister Ingrid Stitt said any further repercussions for those involved were a matter for Tennis Australia, but reiterated the state government's stance against the invasion.
"The Victorian government, let me be very clear, is absolutely opposed to the war in Ukraine — it's abhorrent," she said.
Former Ukrainian tennis player Alex Dolgopolov, who retired from tennis last year and went on to serve in Ukraine's military, took to Twitter to label Srdjan Djokovic's actions "absolutely disgusting".
"Politics should be kept out of sports they said. These people have absolutely no business in being on tennis tournaments, including [Djokovic's] father, if they openly praise a genocidal regime," he wrote.
"The ones saying politics are out of sports, is simply delusional, never was, never will be, and this video is a clear example."