Four gay officers have won their landmark discrimination case against NSW Police after their employer subjected them to an internal drug investigation based on their sexuality four years ago.

Key points: The officers complained about their treatment at Newtown Police Station

The officers complained about their treatment at Newtown Police Station They claimed there was a "homophobic culture" at the station

They claimed there was a "homophobic culture" at the station The station's Commander, Simon Hardman claimed the group was "notorious for their promiscuity"

The NSW Civil and Administrative Tribunal (NCAT) ruled Christopher Sheehy, Steven Rapisarda, Shane Housego and Christian McDonald were "presumed to be engaged in drug use by reason of their homosexuality".

The men claim the 2015 investigation stemmed from a "homophobic culture" fostered by senior management, including Commander Simon Hardman, at Newtown Police Station in Sydney's inner-west.

The tribunal found there was "no culture of bullying" and "harassment" in the workplace, but former Superintendent Hardman was "homophobic" when he referred the men to undergo six months of drug testing.

Mr Hardman, who is now head of security at the University of Sydney, first became suspicious of the four officers after a fifth officer returned a positive result for ecstasy and speed from a hair sample in 2015.

In lodging an official complaint with NSW Police, Mr Hardman said "close friendships" between the five officers and their attendance at bars such as Stonewall on Oxford Street, raised "further suspicion".

Mr Hardman claimed the men were "notorious for their promiscuity" and had a reputation for "loose morals".

"Drug use is thought to be fundamental in such indiscriminate sexual encounters," the complaint read.

But the 2015 investigation found "no direct evidence of drug use" or "related misconduct" against any of the officers.

Today, the court found Mr Hardman "was motivated, consciously or unconsciously, to make complaints ... by reason of their homosexuality".

Lawyer Nicholas Stewart from Dowson Turco Lawyers said his clients were the types of people that belong in the NSW police force, which has come along way in embracing the LGBTQI community.

"Our clients are overwhelmed and vindicated by today's decision and will now be seeking compensation for their significant financial and emotional damages," he said

"This decision reflects that homophobia remains alive in pockets of every workplace, and employers need to do more to protect people, who are vulnerable to harassment and discrimination."

The ABC has contacted NSW police for comment.

Christopher Sheehy said he did not feel supported by his superiors. ( ABC News: Andrew Willesee )

Mr Sheehy, who was a Senior Constable at Newtown Police Station, said he was pleased the four-year ordeal was over.

"It's overwhelming, I'm very relieved, this has been a long time coming," he said.

"It's taken a great toll on me financially and emotionally."

He has left the force.

"It was a career that I once wanted for life, however, ultimately I didn't feel like I was supported by my superiors," he said.

A NSW Police spokesperson said the organisation was "reviewing the decision handed down by the NSW Civil and Administrative Tribunal today and is considering its response".