Nick Kyrgios has called former Australian swimming champion Dawn Fraser "a blatant racist" after she claimed the country's tennis stars should be setting a better example or "go back where their parents came from".

Fraser made the comments in the wake of Kyrgios' fourth-round defeat by France's Richard Gasquet at Wimbledon, where the 20-year-old was criticised for appearing to give up a game early in the second set.

Kyrgios, who denied accusations of shirking, went on to lose 7-5 6-1 6-7 (7/9) 7-6 (8/6), but could face punishment from the International Tennis Federation.

Fraser's comments to Australian Channel Nine's Today programme about Kyrgios' second-set performance moved on to remarks about the heritage of the Canberra-born player, whose father is from Greece and whose mother was born in Malaysia, and German-born Bernard Tomic, who has a Croatian father and Bosnian mother.

Tomic was dumped from Australia's Davis Cup team after hitting out at Tennis Australia earlier this month.

When asked about Kyrgios' behaviour at SW19 and Tomic's war of words with the governing body, 77-year-old Fraser said: "They should be setting a better example for the younger generation of this country, a great country of ours.

"I said they were not good Australians by behaving the way they are on court"

"If they don't like it, go back to where their fathers or their parents came from. We don't need them here in this country if they act like that."

Kyrgios then hit out at Fraser's comments on his official Facebook page.

He said: "Throwing a racket, brat. Debating the rules, disrespectful. Frustrated when competing, spoilt. Showing emotion, arrogant. Blatant racist, Australian legend."

Fraser later denied that her remarks were racist, telling Australian media organisation Fairfax Media: "I'm not a racist person. If you take it that way then I'm sorry that you take it that way, but I'm not racist at all.

"I said, 'If they don't want to be Australians then maybe they should go back to the country where their parents come from'. That's not being racist.

"I can see it being interpreted that way... but it wasn't intended that way. I said they were not good Australians by behaving the way they are on court. Do you think they are?"