Deviant childcare workers are on notice after one received a lengthy prison sentence for sexually exploiting kids.

Labelling David William James' offending as disturbing and depraved, Judge Guy Newton said the crucial importance of childcare centres made the sickening crimes even worse.

James, 28, was sentenced to a maximum of 12 years' jail at Sydney's Downing Centre District Court on Thursday after he pleaded guilty to 11 charges related to the production and possession of child abuse material.

He committed the crimes against children as young as five years old at six out-of-school centres across Sydney between April 2021 and May 2024.

"Childcare centres are of critical importance (and) young children depend upon their carers," Judge Newton said.

"Childcare is often necessary for children to grow up in economic stability ? it is vital parents can have trust in childcare facilities."

James wore a green prison-issued fleece as he sat motionless in a custody cell and watched his fate be handed down.

Judge Newton imposed a non-parole period of seven years meaning James, who has been in custody since October 2024, could first be eligible for release in October 2031.

"In each case he was the child's carer ... the offender abused both a position of trust and authority," he told the court.

"That breach of trust was egregious."

James worked casually at nearly 60 childcare centres during the period of offending, prompting police to notify 1500 parents after he was charged.

Aged between 22 and 26 when offending, he worked as a probationary constable until he failed to pass probation, when he shifted to a civilian capacity until May 2023.

NSW Police said it was unaware he was working in childcare simultaneously.

The sickening crimes included filming children while they were partially undressed and committing a sex act in their presence.

James took children into prohibited areas of the childcare centres before taking photos and videos of them.

Speaking to psychologists after being charged, James admitted he was sexually attracted to children and routinely accessed the dark web to access illegal material.

He had a healthy and stable home life including supportive adoptive parents but was a deviant in private, which Judge Newton likened to him living a dual life.

Federal police found the child abuse material on the dark web and traced it back to James in June 2024.

"Our thoughts are with the children, their families and anyone affected by this horrendous offending," AFP Detective Superintendent Luke Needham told reporters outside court.

"Unfortunately offending in this field spans all sorts of (people) ? I wouldn't point my finger at one particular profession, but law enforcement and all partners, federal and state, are working to protect children."

At previous hearings, victims' parents revealed the pain of knowing their children had been exposed to the predator.

"I no longer consider any person or place safe, I struggle to reconcile the idea that my children are safe anywhere that they are not with myself or my husband," a mother told the court in a letter.

"Most nights I wake up and think about what happened ... I do not think I will ever be able to escape that guilt."

Since his arrest, James has been confined to his cell for 23-and-a-half hours a day and has been ostracised after being identified as working for police.

1800 RESPECT (1800 737 732)

National Sexual Abuse and Redress Support Service 1800 211 028

Lifeline 13 11 14

Kids Helpline 1800 55 1800 (for people aged 5 to 25)