Neville Donohue is serving a jail sentence for perjury, attempting to pervert the course of justice and creating fake medical documents advising a Victorian court he was dying of a brain tumour.

It was a lie. Donohue just hadn't wanted to attend his court case for dishonestly offences.

After he was caught, he lied again and said he was needed for urgent and special military service.

His third appeal against his conviction was labelled an abuse of process and tossed out by Victoria's Court of Appeal on Thursday.

"Unhappily, precious judicial time has once more been expended dealing with another entirely hopeless proceeding brought by this applicant," justices Phillip Priest, Richard Niall and Terence Forrest said in a joint statement.

"The applicant's contention that he had fresh and compelling evidence upon which to rely was utterly devoid of substance.

"In the course of the hearing ... this court explained to him the meanings of fresh and compelling."

Donohue was jailed in 2016 at the age of 66 for a maximum of four years and five months.

His history of dishonesty offences dates back more than three decades. At one point, he pretended to be a decorated major general who served in Vietnam.

In 2010, he claimed he couldn't come to court because he was being treated for a brain tumour and post-traumatic stress disorder.

Letters purporting to be from a doctor to a suburban Melbourne magistrate claimed the tumour was terminal and Donohue had entered palliative care.

His court case for dishonesty offences was adjourned repeatedly and the magistrate was told they would receive a death certificate when the time came.

But it never arrived because Donohue wasn't in palliative care and he didn't have cancer.

When he was caught, Donohue claimed the documents had been obtained and sent to the court by his employer, the Australian Signals Directorate.

After the documents were found on his own computer, he said he couldn't reveal the real name of his doctor, or the name he'd used for treatment, for national security reasons.

Donohue hadn't served in the defence force since a stint between 1970 and 1976.

He was convicted of 19 charges during his fourth trial, after three earlier juries were discharged.

Australian Associated Press