Prominent Indigenous Elder and entrepreneur Mick Mundine has left a court stony-faced as he faces child sexual assault charges.

The 79-year-old brother of late boxer Tony Mundine and uncle of former footballer and boxer Anthony Mundine was arrested on Thursday and accused of sexually abusing a Redfern teenager four decades ago.

Sydney councillor Yvonne Weldon has since publicly identified herself as the alleged victim, then aged 15.

Mundine, who is on bail, sat with his hands clasped for much of the proceedings in Sydney's Downing Centre on Wednesday.

The matter has been referred to the Department of Public Prosecutions and will next be heard on October 28.

Outside court, he did not answer reporters' questions about the case.

NSW Police on Thursday said they arrested Mundine after investigating allegations of a 1986 sexual assault since December.

His lawyer, Fahim Arya, told AAP on Friday he intended to fight the historical charges of sexual assault of a person under 16 years of age, and indecent assault.

Councillor Weldon said in a statement posted on social media she carried a four-decade-long burden that she had not previously detailed publicly.

She had been 15 at the time of the alleged assault.

"I came forward for the children who are here now, and to break the culture of silence that allows abuse to continue," Councillor Weldon said.

"To other survivors of (alleged) abuse in its many forms, you are not alone. It is never too late to speak up and seek support."

Mundine, a Bundjalung man, is the brother of late boxer Tony Mundine.

He is also the uncle of former NRL player and boxer Anthony Mundine.

Mick Mundine has been involved in the Redfern community for decades, including directorships at the Redfern Aboriginal Corporation and the Aboriginal Medical Service.

He has also led the Aboriginal Housing Company for the better part of its 53-year history.

Australian Associated Press