Joel Wilson and Sarah Bowley said they were forced out of the Australian Defence Force after coming out as transgender, despite there being a policy in place to prevent abuse and bullying of transgender officers.

The transition would have had little effect on their ability to perform their job, they said.

The pair, who met as cadets, are speaking out to shine a light on the problems they faced.

Both have made complaints through formal channels, but haven't been satisfied with the outcome.

Mr Wilson and Miss Bowley joined Defence in 2013 and 2011 respectively. Both studied engineering before being diagnosed with gender dysphoria.

Mr Wilson said if he had known he was going to transition, he never would have joined the ranks.

"I don't know what person in their right mind would think, 'oh great, I'll join the Defence Force for a free transition'."

"It would be much easier to work in a civilian capacity and save money and transition than it ever would socially to try and transition in Defence."

Mr Wilson joined in January 2013 and left a year and a half later.

"In deciding to join the military I did not identify as trans," he said.

"I was just a very butch, queer woman.

"I went through basic training at ADFA and within a couple of months I quickly realised it was a very binary place. It was very black and white, and I felt really uncomfortable.

"I wasn't allowed the scope to present in a masculine way. Not that there were written rules, but there were unspoken rules. I quickly realised for me to feel comfortable I'd have to transition."

Miss Bowley said when she joined the ADF in 2011 she was overcompensating with extreme masculinity.

"I was so masculine I was described as the epitome of aggression," Miss Bowley said.

"I went so far to prove to everyone and myself that I was masculine."

But that changed after she attempted suicide twice.

In April 2014, Miss Bowley told her boss that she'd been seeing a psychiatrist for six months and was going through the gender transition process.

The discussion did not go well.

"I went on to say I don't expect it to impact my academics in any way, shape or form, or my role within the division," Miss Bowley said.

"He turned around and stated, 'wait there'."

Miss Bowley said he returned with two options for her, leave without pay or discharge. Within three days, Miss Bowley said, she was removed from training, university and her division.

Mr Wilson's transition wasn't easy either.

"I was pretty quickly the subject of the rumour mill at ADFA," Mr Wilson said.

"There was social isolation and discrimination, particularly medically. All expenses paid - not at all," he said.

Both Miss Bowley and Mr Wilson were medically downgraded against their wishes and despite their physical ability. A spokeswoman for Defence said members who were transitioning gender were not automatically downgraded.

"Some Defence members who present with medical conditions may have their deployable status reclassified whilst undergoing treatment," the spokeswoman said.

"This is a duty of care requirement to ensure members are provided with proper support and the opportunity to recover and return to their previous work or a new role within the ADF."

Mr Wilson fought an "uphill battle to get anything medically", which was hard, particularly for a person who had large breasts to take part in men's activities.

"I was told that a double mastectomy was like if someone became obese they would pay for gastric banding surgery - because it was their fault."

Mr Wilson said this was despite the fact he was expected to change in communal areas, and swim with his top off, "because there were expectations that men in the military have to fill, but I couldn't because I'm walking around wearing a binder with large boobs".

"Trans men talk about having breasts is hard for them, well it's only amplified by being in the military, trying to do training, intense physical exercise when you're wearing a really really tight compression vest in the middle of summer."

In 2010, the Australian Defence Force enacted a policy committing to allowing transgender people to serve.

Australian Catholic University associate professor Noah Riseman is studying the history of LGBTI personnel in the military. He said the policy stated full support for members transitioning gender.

"You couldn't be openly transgender in the Defence Force until September 2010," Professor Riseman said.

"Before 2010 if you were transgender you couldn't transition, you basically had to suffer in silence with gender dysphoria."

But, he said after the policy came into effect, the ADF struggled to know how to deal with transitioning members.

He said a policy vacuum until about 2015 meant commanding officers were left to deal with the situations at hand.

Professor Riseman said from what he'd heard of the experiences of Mr Wilson and Miss Bowley, the way they were treated was not consistent with the policy in place to support transgender people in the defence force.

"The leadership team within Defence talk the talk, but the experiences of these people [Mr Wilson and Miss Bowley] are questioning whether they walk the walk," Professor Riseman said.

However, Professor Riseman said LGBTI ADFA cadets who joined the ranks more recently seemed to be having better experiences with their transition in the defence force.

"I do believe the culture is changing for the better. It's not perfect, and no-one is going to pretend it's perfect, but it's improving."

But it happened too late for Mr Wilson. He left the ADF and paid for a double mastectomy himself. He went through the process to file complaints, but said for his own mental health he felt it was best to let it go.

Mr Wilson later found out the ADF had been investigating him for allegedly defrauding the government.

"I was only told afterwards that someone under the whistle-blower scheme had placed a complaint saying that I was defrauding the Commonwealth of money to transition," Mr Wilson said.

"They decided I wasn't fraudulent."

A spokeswoman for the ADF said of the 590 personnel they have investigated for fraud over the past five years, only one was in relation to gender transition.

Mr Wilson said after that, he decided to focus on the future and not the past.

"I decided to step away from it and focus my energy on other things where I can make a difference."

He enrolled in a bachelor of science at ANU, double majoring in mathematics and statistics.

Miss Bowley also left the ADF but continues to suffer from poor mental health due to her experiences during her time there.

Mr Wilson and Miss Bowley said they were ultimately forced to acknowledge their gender dysphoria in the Defence Force, where rigid gender roles have always played a part.

Miss Bowley said despite correcting her gender, she felt isolated from both the men and the women.

ANU College of Law associate professor Wayne Morgan, an expert in queer legal theory, said when gender was so rigidly defined, that's when people can start to question their identity.

"There are very rigid and defined categories," he said.

"You might identify as male but you might say 'hang on a minute, I don't fit all of those'. That's going to lead you to question things."

Professor Morgan said strict gender roles - which were institutionalised in the military - caused discrimination.

"If we had more fluidity in the concept of what it would be to be male and female I think there would be less discrimination in society," he said.

High-profile transgender advocate and former Defence Force member Cate McGregor has previously said in joining the Army it was to "quell disquiet about my gender". Ms McGregor joined as a cadet, but didn't transition from male to female until she was in her 50s and well into her career. It was her status at the time that helped her transition more smoothly, she said.

UNSW Canberra researcher James Connor is examining abuse and bullying in the Australian Defence Force, and said the military "desperately" needs to improve diversity in order to stamp out outdated attitudes and behaviours.

"Abusers tend to target people who are considered outsiders, those who don't fit in," Dr Connor said.

"Bullying and abuse happens on the basis of people being different, but if everyone is a bit different, then you can't [have that]," he said.

"Any organisation that has more diversity does better."

A Defence spokeswoman said the military was committed to creating a safe, supportive and inclusive workplace for all.

"Defence won't comment on individual cases but we can advise that there are a range of policies and practices in place that represent a zero-tolerance approach to bullying, homophobia and transphobia," the spokeswoman said.

"This is because all Defence personnel, including those with diagnosed health conditions such as gender dysphoria, deserve to be supported and treated with respect. Across the country, and around the globe, these members have served with distinction and Defence is exceptionally proud of the contributions they have made."

Mr Wilson, who believes he was the first person to transition while at ADFA, said he hopes the situation has improved since his time there.

"It was the scariest thing I've done, to be honest," he said, of coming out while in the defence force.

"I'm pretty happy to say I've come out the other side of it, not without turmoil and not without having some pretty rough times with my mental health as a result of what happened in Defence. But I've made it out the other side, and I'm happy.

"I'm now at that point where I finally feel comfortable in my own body again."