The new recording came as Sterling's wife expressed interest in holding on to the Clippers, the Los Angeles Times reported, even as league officials worked to force a sale of the team.
Entertainment website Radar Online posted a recording of Sterling talking about race, which it said it obtained from an anonymous source. Radar said the source signed an affidavit confirming the voice was that of the 80-year-old billionaire.
"You think I'm a racist?" Radar Online quoted Sterling as saying on what it reported was a secretly recorded phone conversation. "You think I have anything in the world but love for everybody? You don't think that! You know I'm not a racist!"
Radar included the recording in its report. Reuters could not independently confirm it was Sterling's voice on the recording, and a Sterling representative could not be reached for comment on Thursday.
The NBA fined Sterling $2.5 million (£1.5 million) last month and banned him from the league for life after the website TMZ.com posted a separate audio recording of a voice said to be his that made derogatory remarks about black people.
The comments sparked outrage from players and fans, and led NBA Commissioner Adam Silver to ask team owners to force Sterling to relinquish ownership of the Clippers in what would be an unprecedented step under the league's constitution and bylaws.
"How can you be in this business and be a racist?" Sterling said on the new tape, according to Radar Online. "Do you think I tell the coach to get white players? Or to get the best player he can get?"
The new tape emerged as the Los Angeles Times reported on Wednesday that Sterling's wife, Shelly, said she intended to remain an owner of the team and has hired a law firm as the NBA moved to terminate her husband's ownership.
Shelly Sterling, who shares ownership of the Clippers through a family trust, contended the sanctions against her husband do not apply "to me or my family," according to the newspaper. An NBA spokesman declined to comment on the report.
A representative for Shelly Sterling could not be reached immediately for comment on Thursday. But in a statement, she denied the league had let her know it would prefer she not attend Clippers playoff games this Friday and Sunday.
"As co-owner, I have attended games for 33 years and I will continue going to playoff games as the Clippers march towards a championship," she said in the statement.
Silver was asked at a news conference last month whether any of Sterling's relatives, including his wife, might exercise an ownership or managerial stake in the team.
"There have been no decisions about other members of the Sterling family," Silver said at the time. "This ruling applies specifically to Donald Sterling and Donald Sterling's conduct only."
Sterling purchased the Clippers for $12.5 million (£7.4 million) in 1981, when it was based in San Diego. The team is now estimated to be worth at least $575 million (£339.4 million), according to Forbes, which compiles a list of professional sports team values each year.
The Clippers are currently tied with the Oklahoma City Thunder in the second round of the NBA playoffs at one game a piece. Their next match is scheduled for Friday.
- Sports & Recreation
- Radar Online
- Shelly Sterling