Sampieri, 55, on Thursday pleaded guilty to three counts of child rape in Sydney's Central Local Court after the attack in a Kogarah dance studio bathroom in November 2018.

The attack on the girl ended when two people burst into the bathroom and tried to apprehend him. It later emerged Sampieri had been out on parole after raping a woman years earlier.

On Thursday, he also admitted detaining the girl, choking her, committing two indecent acts while filming her, indecently assaulting her and wounding with intent to cause grievous bodily harm.

As a result of the 10 guilty pleas, five other charges were withdrawn.

A bearded Sampieri appeared via video link from custody as his lawyer, Penny Musgrave, entered the pleas on his behalf.

The court heard some facts were still in dispute despite the guilty pleas.

Sampieri was committed to Downing Centre District Court for sentence on June 21 when he's again due to appear via video link.

The rapist also faces 29 charges of making threatening phone calls in the weeks before the dance studio attack. He's due to appear before Central Local Court on July 10 on those matters.

A police officer is separately facing charges of neglecting his duty for allegedly mishandling a complaint about the paroled rapist in early November.

Leading Senior Constable Andrew Michael Bruce has pleaded not guilty to all four charges and is currently suspended with pay.