A recidivist sex offender who was jailed for multiple offences including keeping his daughter as a sex slave is about to be released from prison.

However, Ronald Van Der Plaat's request for parole just weeks out from his official release in May has been declined to the Parole Board's concerns at his medium-to-high risk of reoffending and inability to monitor who he is contact with when he's let in eight weeks.

Van Der Plaat is now 82 and was sent to prison for 14 years in 2000 for raping his daughter and subjecting her to "bizarre and depraved" abuse, which the sentencing judge said amount to "indescribable cruelty".

He was released in 2010 on strict conditions, but was jailed again after committing further offences in 2012 including making an intimate visual recording.

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Van Der Plaat, who continues to deny his offending, faces release as he would have served his full sentence of 15 years and 10 months, an legally he can no longer be held behind bars, despite community probation declaring he still "remains an undue risk to community safety".

In its decision released today, the board declined his latest parole request partly because he had not obtained any treatment for his offending during his stint in prison.

The Department of Corrections confirmed that Van Der Plaat was eligible for an extended supervision order.

Before his release, the board wants confirmation that Van Der Plaat has suitable accommodation to not only take into account the safety of the community, but also his age and declining health.

A geriatrician assessment revealed he is suffering mild cognitive impairment because of the supervised environment of prison.