According to police, two men got into an altercation about 1.30pm outside the hotel on George Street.

In a video posted online by New Zealand UFC fighter Dan Hooker, a man who appears to be Werdum, 40, can be seen gesticulating and pointing at Covington, 29, before launching a boomerang at him from close range.

The boomerang strikes Covington in the neck, but it does not return to the thrower.

The boomerang was in a plastic shopping bag, but flew out of the bag as it struck Covington, who caught the bag.

The man who appears to be Werdum is seen calmly collecting the boomerang, picking it up off the ground as Covington walks away.

In an Instagram video posted by Covington, which has since been removed, he calls Werdum "a f---ing clown" and uses an anti-gay slur against Werdum.

"You just punched me in the face, you wanna come punch me again bitch?" Covington said in a foul-mouthed tirade.

"F--- Brazil, bunch of filthy animals," he said.

In an interview with MMAjunkie.com, Werdum accused Covington of kicking him and calling him a "Brazilian animal". Werdum denied Covington's claim that he punched him.

It is not the first time Covington has attracted controversy for his anti-Brazilian comments.

After defeating Demian Maia in a fight in Sao Paulo in October, Covington called Brazilians "filthy animals" in another verbal barrage.

Werdum, a former UFC heavyweight champion, is in Sydney for a clash against Polish fighter Marcin Tybura on Sunday, while Covington is on a promotional visit.

On Friday morning, police confirmed they had charged a 40-year-old man with common assault.

In a statement the UFC it was aware of the "altercation" and "will conduct a full investigation to determine if the athlete conduct policy was violated before taking any further action on this matter."

Werdum is expected to appear at Downing Centre Local Court on Wednesday 13 December 2017.

Police said Covington did not require medical treatment after the attack.