Wayne Wilmot was ordered to spend another two years behind bars in 2019, despite having served his jail term.

That continuing detention order (CDO) expires on September 23, which led the State of NSW on Friday to apply for an interim detention order (IDO) in the Supreme Court.

The State wants him to stay behind bars until Justice Julia Lonergan can hear its application for Wilmot to be subject to an extended supervision order (ESO) on his eventual release.

Wilmot's extensive criminal history officially began with a sex attack on a woman walking through a park when he was 13, after which he said "I've ... got a problem" and "This is not the first time I've done this".

He served eight years for the abduction and rape of Ms Balding.

The 20-year-old bank teller was grabbed from a Sydney train station by a gang of homeless youths before she was repeatedly raped.

Wilmot remained in the car when Ms Balding was then bound, gagged and thrown over a fence before being held underwater in a dam until she drowned.

He has committed sexual offences against woman and men, involving at least eight victims including a woman he beat, bound and raped at another Sydney train station in 1998.

The sentencing judge found the victim "was subjected to extreme brutality and sexual violation", which had a devastating impact on her.

In granting the CDO in 2019, Justice Lonergan noted Wilmot's "appalling criminal history and pattern of offending" and his repeated denials and/or chilling minimisations of his violent sexual offending.

He also blamed his victims, lacked insight, and had a personality disorder and antisocial and aggressive traits and behaviours.

"I am satisfied to a high degree of probability that the material relied upon by the State establishes that the defendant poses an unacceptable risk of committing another serious offence if not kept in detention under the order," she said.

Wilmot's lawyer on Friday did not oppose the granting of the IDO until the judge considers the application for his extended supervision in the community.

The judge previously refused an application to suppress Wilmot's name.

Australian Associated Press