06/03/2016 3:44 PM AEDT | Updated 15/07/2016 12:51 PM AEST

Kyrgios Fires Back Over Claims He Chucked A Sickie To Avoid Davis Cup Match Up

Michael Dodge via Getty Images
MELBOURNE, AUSTRALIA - MARCH 06: Bernard Tomic of Australia reacts after he loses a point in his match against John Isner of the USA during the Davis Cup tie between Australia and the United States at Kooyong on March 6, 2016 in Melbourne, Australia. (Photo by Michael Dodge/Getty Images)

Nick Kyrgios has fired back at friend and fellow Australian tennis player Bernard Tomic over claims he chucked a sickie to avoid a Davis Cup tie against the U.S. team.

On Sunday, Tomic appeared to say Kyrgios was faking illness to escape playing against the U.S. team in an elimination round.

Courtside microphones picked up the sledge as Tomic lashed out at Kyrgios in frustration during a change of ends.

“Nick’s sitting down in Canberra. Bulls**t he’s sick,” Tomic said to Davis Cup team captain Lleyton Hewitt.

Kyrgios was ruled out of the match-up several days ago with a virus.

On Sunday evening, Kyrgios took to Twitter to vent his feelings about his mate's comments.

"Heat of the moment, not gonna take it personally. Indian wells a week away, plenty of time," Kyrgios said in reference to an upcoming tournament, the Indian Wells Masters, he is set to play in.

"Just don't expect me to have your back anytime soon," he tweeted soon after.

In a press conference after his match, Tomic said he'd be disappointed if Kyrgios played in the tournament.

"If he plays Indian Wells, then he's definitely lost a little bit of my respect," he said.

He said the pair spoke after the match and Kyrgios indicated he would play.

"One of the questions I asked him was 'are you playing Indian Wells?', and he was like 'Yeah, I should. I'm still sick but I'm gonna be better tomorrow'."

"It's just weird for me. I've said enough. At the end of the day it's just disappointing to not have him here. He's an amazing player and it would have been important to have him here."

Kyrgios' absence on Sunday meant Tomic, Hewitt, John Peers, and Sam Groth were left to face off against the higher-ranked U.S. team.

U.S. player John Isner took the match against Tomic in four sets, winning 6-4, 6-4, 5-7, 7-6.

The victory means the American team are safe from elimination, as they have a 3-1 lead with only one game to play in the tie.