More than 200 sailors, some of them still serving, have joined a class action against the Royal Australian Navy alleging they were tricked into signing up for four years under false promises they would leave with a trade.

Key points: More than 200 sailors claim they received no training

More than 200 sailors claim they received no training Say they were strung along with empty promises

Say they were strung along with empty promises Trainee says experience impacted mental health

Instead, they claimed they received no training and little practical experience and were left twiddling their thumbs for months at a time.

In a case filed late last week, 220 of them are suing the Navy for negligence and breach of contract.

Former sailor Clayton Searle was 18 when he signed up. He had just left school and was struggling to find work in his home town of Rockhampton in Queensland.

"One day mum suggested the idea of what about the military and no-one I'd known had joined the Navy," he said.

"I like getting out on the water and I thought it would be a pretty interesting career and it definitely seemed it from the website."

Mr Searle joined up under a program known as MT2010 and was given a contract that said he would receive training leading to a trade certificate IV in engineering.

But at the end of his four years he still had no qualification. He alleges the recruitment process was dishonest and the Navy strung him along with more empty promises.

"At the four-year mark they were offering new courses to act as compensation for where they had gone wrong but it was still three years before we'd receive a lesser qualification than what we were scheduled to have," he said.

Trainee says time 'spent sitting around waiting'

Former trainee Jon Henderson from Sydney was in the same intake.

"As my career progressed it was quite obvious that we were never going to get the training as promised and all along the way the Navy were in the position of power and we were always beholden to what the Navy dictated to us," he said.

He said much of his time in the Navy was spent sitting around waiting.

"I was basically warehoused in a site called PSU or Personnel Support Unit where numerous sailors basically sit around, read the paper, go online," he said.

He said most of the work was done by contractors and there was little opportunity for the promised training.

"Kids are going in there at 17, 18 and leaving with nothing. There are guys who've been in there 10 years and are coming out and having to do excess training just to get a qualification to get a civilian job," he said.

Their lawyer Stewart Levitt said these stories were just the tip of the iceberg.

"The disappointing reality has been that hundreds of Australian apprentices and graduate students were placed in a position where they were enticed to join the Navy with a promise of a certificate IV in engineering, when the Navy had never developed a program let alone had any demonstrable, sustainable intention to provide the course," he said.

Mr Levitt said billions of dollars was being wasted.

"These people have been paid salaries to do nothing by the Australian taxpayer for the last four years, to play cards, to be miserable and to be made miserable," he said.

He alleged that sailors who complained were locked in a room and pressured to sign a release clearing the Navy of its training obligations.

Others, he said, were punished by being sent on undesirable assignments.

"I have spoken to a number of trainees who were despatched to chase boat people back to Indonesia for example," he said.

Experience took toll on trainee's mental health

After years working as a concreter 24-year-old Mitchell Cupitt joined up in October 2011, enticed by the prospect of a qualification as an electrician.

"I wanted to get a trade and travel the world," he said.

Instead he also ended up at the PSU.

"We used to go to work and do pretty much nothing all day. We'd get our name marked off and fight over a lounge to get the comfiest seat," he said.

The experience took a toll on his mental health.

"I had a bit of a rough patch, I suffered from depression. I was diagnosed while I was in. It wasn't just me suffering, everyone was," he said.

Mr Cupitt left the Navy after two years and is now back concreting.

"I was lucky I got out and had something to fall back on. I just don't want this happening to anyone else," he said.

"They've done the wrong thing by everyone."

In a statement, the Department of Defence said: "Navy is aware of the concerns raised by some current and former marine technicians, who joined the Navy under the Marine Technician 2010 Career Continuum, and has engaged with those affected."

"Navy's position is to solve this training issue," the statement said.

"Unfortunately, as a result of the legal proceedings being commenced, the Navy is unable to comment further."

The case is due to come before the NSW Supreme Court on May 20.