Liar, medal cheat, wannabe, valour thief — those are a few samples of the insults you'll find on the website run by the Australia and New Zealand Military Imposters Group (ANZMI).

Key points: ANZMI post on their website names and photos of people they claim are guilty

ANZMI post on their website names and photos of people they claim are guilty Members of the website say anonymity is important for them to operate

Members of the website say anonymity is important for them to operate The CEO of Veterans 360 says the website is often used to vilify veterans

ANZMI have investigated hundreds of reports of people either inventing or embellishing their service record.

More than 300 of those cases, complete with names and photos, are published online by the anonymous group.

ANZMI claim they have never been wrong, but its detractors argue the group unfairly destroys the reputations and mental health of people, many of whom are also veterans.

One of the small number of people who run ANZMI is a man who goes by the pseudonym Neville Trueman.

He feels strongly about the group's work.

"If you go to war, you come back a different sort of a person," Mr Trueman said.

"It's just simply not right that people will falsely claim that they've been through that experience."

The group, he said, receives reports from all over Australia, which are then investigated.

About 40 per cent are considered to be proven, according to Mr Trueman, and their subjects named and shamed on the ANZMI website.

He said once information about a possible false claim is sent to the group, they begin an investigation to determine whether that person "is or is not a fraud".

"A true veteran can always pick them," Mr Trueman said.

"Because these people were always [claiming to be] a sniper in the SAS, their documents are sealed and secret and no one can get them — that's all nonsense."

Mr Trueman said he had spent more than 20 years in the army, including service in Vietnam and Papua New Guinea.

He and the other members of the ANZMI refuse to disclose their identities.

"If we didn't operate covertly, we wouldn't be able to operate at all," he said.

Website used to vilify ex-service personnel

But ANZMI cuts a polarising figure in the Australian veteran community.

Jay Devereux, founder and chief executive officer of Veterans 360, an organisation which helps homeless ex-servicemen and women, said the site does a lot of good but also sometimes harm.

"What I've seen is an ever increasing use of this site to vilify ex-service personnel," Mr Devereux said.

He points to one particular case of a man he said suffered major trauma during a period of seven years serving in the Australian Defence Force.

"[He] unfortunately wore one medal on an Anzac Day I believe that he was not entitled to wear," he said.

"He acknowledged to ANZMI that he'd done the wrong thing, he wrote a very detailed and heartfelt apology."

ANZMI have investigated hundreds of reports of people either inventing or embellishing their service record. ( ANZMI )

ANZMI named him on their website anyway, and Mr Devereux said as a result the man was ostracised by the veteran community.

Mr Devereux said the report also caused him to be fired and kicked out of his accommodation.

"Over the past two years he has contacted me at least five times when he's been suicidal and indeed ready to take his own life," he said.

"And invariably the first thing he points to is as soon as you Google his name, the first thing that comes up is the ANZMI post."

Mr Devereux said he did not want the site shut down, but change was needed.

"If somebody has signed up the Australian Defence Force, they have given essentially their lives or a cheque to say to that you can take my life if needed," he said.

"I think it's very important and absolutely vital that we take care of those individuals, and don't allow them to be vilified on these sorts of sites."

Mr Trueman said he was aware of that particular case and "we certainly don't like it".

"To the best of my knowledge no-one has ever [died by suicide] as a result of being on our website," he said.

Ultimately, the ANZMI said it blamed the subjects of its reports for any fall-out.

"It's like a person blaming the police for them going to jail," Mr Trueman said.

"It's not the actions of ANZMI that have got them in the position that they're in, it's their lives and their actions."