In short:

Matthew Stephen Cameron has pleaded not guilty to 10 charges over alleged sexual offences against three younger NSW Police colleagues.

An investigation into the allegations began in mid-2023 and Mr Cameron has since resigned from the NSW Police Force.

His District Court trial has heard the 33-year-old maintains the sexual acts were consensual.

A former NSW Police officer is on trial for allegedly sexually touching three younger male colleagues and sexually assaulting one of them before resigning from the force.

Matthew Stephen Cameron, 33, has pleaded not guilty to 10 charges, including nine counts of sexual touching without consent and one count of sexual intercourse without consent.

The District Court trial started on Monday, where Crown prosecutor Damien Hannan told the court Mr Cameron touched his younger colleagues' genitals without their consent during or after social gatherings between December 2021 and April 2023.

The court heard Mr Cameron was a constable at Northern Beaches Police Area Command (PAC) at the time, where he worked with the three alleged victims.

The court heard all three complainants were probationary constables at the time of the alleged offences and the Crown will argue that Mr Cameron's position, being a more experienced officer of a higher rank, was an aggravating factor.

Acts were consensual, defence argues

Defence barrister Margaret Cunneen SC told the court her client "has a very different version of events" and maintained the sexual acts were "completely and quite enthusiastically consensual".

The court heard Mr Cameron was an openly gay man, who was acting as the gay liaison officer at the Northern Beaches PAC, while the alleged victims were heterosexual men.

Five of the charges relate to one alleged victim after he joined the force in 2021.

After one social event in March 2022, Mr Cameron allegedly touched his colleague's penis while he was heavily intoxicated and "drifting in and out of consciousness".

The court heard Mr Cameron then performed oral sex on the man without his consent before the man "pushed him away when he realised what was going on".

The alleged offences happened while the man's girlfriend was asleep in another room.

Mr Cameron is also accused of touching the same man's genitals without his consent at a campsite in 2022.

In June 2022, the court heard Mr Cameron touched another colleague's genitals without his consent while they were sleeping on a couch after a social event.

The next morning, the court heard Mr Cameron allegedly climbed into bed with the man and touched his genitals before the man said "don't touch me, you know I'm not gay".

In late 2022, the court heard Mr Cameron and a third young male colleague had returned to a private home together after a social event, where Mr Cameron allegedly grabbed the man's genitals without his consent.

He then allegedly kissed the same man on the lips without his consent at a social event in April 2023.

An official investigation into the allegations began in mid-2023.

Mr Cameron has since resigned from the NSW Police force.

Ms Cunneen SC told the court the allegations were "completely and utterly denied" by Mr Cameron, who maintains all interactions with the three men were consensual.

"There was no criminality in anything that took place at all," Ms Cunneen told the court.

"Mr Cameron is a person of utterly unblemished character."

The jury trial is expected to run for three weeks, with the alleged victims' testimony being heard in a closed court.