A Korean national accused of assaulting two women was released by immigration officials in Sydney before being arrested again, according to police.

Yong Seok Ji, 25, was arrested earlier this month after being accused of indecently assaulting a woman in May and sexually assaulting another woman in June in Sydney's CBD.

In a statement to the ABC, police confirmed the man was released after being taken to the Villawood Detention Centre.

"He was taken to Day Street Police Station where checks revealed he was residing in Australia unlawfully on an expired visa," police said.

"Police notified [the] Department of Immigration and the Korean national was taken into custody at Villawood Detention Centre.

"Police advised immigration officials they were making inquiries in relation to the alleged sexual assaults.

"The following day, detectives from the State Crime Command's Sex Crimes Squad were informed by the Department of Immigration that they received legal advice indicating that they were to issue the [person of interest] with a bridging visa.

"Shortly after police were informed the male had been released."

Officers continued their inquiries into the sexual assault and arrested the man again on Tuesday.

He was charged with sexual assault, five counts of indecent assault and common assault.

He will remain behind bars until his next court hearing in September.