A Sydney doctor is facing fresh charges over the alleged sexual assault of several patients.

Detectives in June began investigating allegations of sexual touching and assault by a doctor against two women at his Arncliffe practice.

A 28-year-old woman was allegedly indecently assaulted during a consultation on June 4, police said.

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Then on June 26, a 19-year-old woman was allegedly sexually assaulted during a consultation at the same medical centre.

Following police inquiries, a 45-year-old man was arrested at the practice on July 12.

He was charged with sexual touching without consent and sexual assault.

The matters remain before the court.

Now, police have identified another victim, whom the doctor allegedly sexually assaulted in June.

He has since been charged with sexually touching another person without consent, and sexual intercourse without consent, police said on Wednesday.

The doctor is due to appear at Downing Centre Local Court in September.

The investigation is continuing.