A senior police officer has pleaded not guilty to neglecting his duties after he was accused of failing to get convicted sex offender Anthony Sampieri off the streets before he allegedly raped a young girl in a Kogarah dance studio.

Senior Constable Andrew Bruce chose not to face the Downing Centre today and instead was represented by his lawyer who said it had been a "troubling time for the officer and his family".

In October 2018 it is alleged Senior Constable Bruce, 31, interviewed Sampieri, after a woman accused him of making a harassing and obscene phone call.

After the interview, Sampieri — who was on parole at the time — was allowed to leave.

It is alleged Sampieri should have been taken into custody at the time police interviewed him.

The next month, Sampieri, 55, allegedly raped and choked a seven-year-old girl, while filming the 15-minute attack inside a locked cubicle in the men's bathroom of a Kogarah Dance Studio, in Sydney's south.

Two men kicked down the door and then Sampieri allegedly stabbed one of them several times before being arrested and subdued on the ground outside the building.

Sampieri was charged with multiple offences, including aggravated indecent assault, kidnapping and wounding a person with intent to cause grievous bodily harm.

Police at the scene of the incident where a seven-year-old girl was allegedly attacked in a toilet block. ( ABC News )

After further investigations, he was charged with offences relating to phone calls he allegedly made to dozens of women.

At the time, NSW Police Commissioner Mick Fuller previously said Sampieri would have been behind bars had "the senior constable" charged him with making an obscene phone call while on parole.

Last year, a NSW Police investigation revealed a woman made an official complaint at St George Police Station about a harassing and obscene phone call allegedly made by Sampieri.

The offence of criminal neglect of duty doesn't carry jail time, but if convicted, Senior Constable Bruce would no longer be able to work in the police force and could be fined up to $2,200.

Outside the Downing Centre, his lawyer Warwick Anderson said there was no doubt his client would defend the matter.

"It's a very troubling time for him and his family," he said.

"It's a nasty type of case, the allegations are very tough, he's been accused of neglecting his duty.

"He is a young man, he has had his life turned upside down.

"The Police Association is providing him with support, but in terms of the hierarchy, well I can't comment on that."

The case returns to the Downing Centre on August 8.

Sampieri remains behind bars at Silverwater Jail.