A spectator yelled two racial slurs which were picked up by microphones in the arena while San Antonio guard Mills was shooting free throws against the Cleveland Cavaliers in Cleveland on Monday [AEDT].

"Hey, Jamaican dog. They want their bobsledder back," the spectator shouted as Mills lined up his first shot, and then they backed it up again.

"Jamaica just called; they want their bobsledder back."

Mills was born and bred in Canberra to a Torres Strait Islander father, Benny, and Aboriginal mother, Yvonne, and he has never forgotten his roots.

"I am a proud Islander," Mills wrote on Twitter after the game.

"Like my Jamaican Brothers, me & my family in the islands of the Torres Strait have experienced racial slurs for decades. Hope your efforts will enlighten this confused, hateful fan."

It comes as Black History Month draws to a close in the United States, with the fan being slammed on social media.

The disgraceful comments did little to unsettle Mills as he moved into fourth on San Antonio's all-time three point scoring list during a 110-94 win over LeBron James's Cleveland Cavaliers.

LaMarcus Aldridge scored 27 points while Danny Green added 22 as the Spurs snapped a four-game losing streak.

Dejounte Murray added 13 points, while Bryn Forbes (12), and Kyle Anderson (10) all made solid contributions.

Australian shooting guard Mills added five assists in 35 minutes on court as San Antonio improved to 36-25 to be third in the western conference.

James had 33 points, 13 rebounds and nine assists for the Cavaliers, who fell to 3-2 since overhauling their roster with three deadline-day trades.

Cleveland are 35-24 and third in the east.

with AAP