Three female firefighters have quit amid allegations of indecent assault, sexual harassment and bullying at a station in regional NSW.

Key points: One of the women claims she was groped by a male colleague

One of the women claims she was groped by a male colleague Another told the ABC there was "a culture of fear" at Dungog Fire Station

Another told the ABC there was "a culture of fear" at Dungog Fire Station Fire and Rescue NSW is investigating

Renae Thompson, Natalie Newton and Claire Briggs say when they complained to Fire and Rescue NSW (FRNSW), management forced women at Dungog Fire Station to work from a disused garage so they could be separated from male colleagues.

The trio all left the organisation in the past six months, claiming there was a toxic "bully-boy" culture at the station, which is in the state's Hunter region.

In a show of support, two men also resigned.

FRNSW is now investigating the circumstances surrounding the mass departures.

Women were forced to work from this old garage. ( ABC News: Paige Cockburn )

Ms Thompson signed up as part of a 2012 recruiting drive directed at women, and alleges she was groped by a male firefighter from the station in April 2017.

She complained to FRNSW in December 2017.

"I just froze. I tried to just forget it, I didn't want to report it," she said.

"I'm an educated person, I know how these things work, usually when a woman comes forward with something like this the woman will lose her job."

There was no way to access emergency incident information from the leaking garage. ( Supplied )

FRNSW investigated after receiving the complaint, but found it was "highly unlikely" further action was needed.

"These are allegations and with allegations, comes great responsibility to demonstrate what occurred," Assistant Commissioner Paul McGuiggan said.

The women say they were treated as "troublemakers" and faced discrimination that varied from not being allowed to drive trucks, having uniform requests denied and being subjected to misogynistic language.

Ms Thompson claims in one instance she was told by a male FRNSW employee to "get on your knees, where you belong".

Claire Briggs said she felt physically ill while she was at work. ( ABC News: Paige Cockburn )

Ms Briggs, a former Police Officer in the UK, described FRNSW as a "boy's club".

"There is a culture of fear which is a dangerous culture in a rescue environment," she said.

"Information and communication is severely supressed and controlled so as to prevent transparency."

But Assistant Commissioner McGuiggan put the problems down to a "history of interpersonal conflict" at Dungog station.

"The issues raised at Dungog certainly got our attention," he said.

"But there's been a lot of work done over several years, over a host of allegations, and a lot of communication back and forth to the individuals making the complaints."

Natalie Newton said she felt the men she worked with had free reign to harass her. ( ABC News: Paige Cockburn )

Ms Newton told the ABC a male colleague pressured her for sex over several months between 2013 and 2014.

"Numerous times I was asked if I would have sex on the truck or one of the rooms ... here there and everywhere," she said.

"Out on jobs I always had comments made in a sexual nature."

She complained to FRNSW in 2014, but claimed she continued to be rostered alone with the man until 2018.

'I'd just get ignored'

The trio claim Dungog Fire Station had been plagued by a culture of misogyny for years before women and men were separated.

The garage FRNSW forced the women to work from was dilapidated and leaking, with no computers to receive information about emergency call-outs.

"We were told to come up to the driveway and yell out to the men 'what's the job?'," Ms Thompson said.

"But I'd just get ignored ... I was nothing, I was nobody."

FRNSW investigated the station in August 2018, but the trio say nothing happened.

FRNSW Director of People Michael Baldi is expected to hand down his findings from a second probe, into the mass departures, soon.

The women said they joined Fire and Rescue NSW to give back to their community. ( ABC News: Paige Cockburn )

Assistant Commissioner McGuiggan said the segregation was to provide privacy and dignity.

"It's not ideal, and we certainly don't want to inconvenience anyone or suggest that people have been discriminated against in any way," he said.

"I'm not going to hide from it, it's a challenge for us, but it's one we are trying to address.

"In the next two years we will be building a new fire station in Dungog."

Ms Thompson said she could not work at the station any more and was medically discharged in July this year after Safe Work NSW found she sustained psychological injuries from her time at FRNSW.

On top of the two internal investigations, Assistant Commissioner McGuiggan did not rule out an external probe.

"Are we perfect? No. But we won't stop until we get there," he said.

"We would still like to work with those individuals to see if we can make their lives a little bit more comfortable."

Ms Thompson's husband Matthew resigned from the station in protest over the way the women had been treated, as did another male colleague, Bradley Bale, who said he was also bullied.

Mr Thompson said he saw "bare-faced lying" turn into a full "gender apartheid".

His wife now has a dire warning for women planning on becoming firefighters.

"Don't do it, it's a troubled organisation," Ms Thompson said.

"You'll be chewed up and spat out."