A military court-martial panel in Canberra found Captain Stefan King, 48, guilty of seven counts of obtaining financial advantage - three of those by deception, which is a more serious charge. The latter three counts carry maximum penalties of 10 years' jail each.

In a twist to the case, in which the accused's love life was laid bare in often brutal detail, Captain King, the former commanding officer of the HMAS Albatross in Nowra, told the court he'd been threatened via email by a superior officer in the military. The email indicated some defence force colleagues wanted Captain King to go to jail, his lawyer suggested.

Captain King will be sentenced Thursday morning. Other possible penalties include dimissal from the Navy, paying reparations, loss of rank or a simple reprimand.

A panel of five of his peers - all Navy captains - found him guilty of claiming about $15,000 worth of food, rent, travel and utilities allowances to which he was not entitled. The panel cleared him of a further nine charges. Three of the original 19 charges were not proceeded with.

Prosecutor Lyn McDade had argued that Captain King was not entitled to the allowances - which are paid to navy members posted away from their spouses - because he was already emotionally and sexually separated from his then wife, Captain Jacqueline King, when he was posted from Canberra to HMAS Albatross.

In dozens of emails tendered as evidence by the prosecution, Captain King repeatedly declared his love for married Sydney woman Robina Frew and declared his intention to marry her. The emails also revealed he had had two other affairs around the time of the posting.

Captain King, supported in court yesterday by his former wife and his sister, told the panel in pre-sentencing submissions he was "utterly devastated" by his removal as commanding officer and said he believed his career was now ruined.

Questioned by his defence lawyer, Commander Sandy Street, Captain King also said he had received a threatening email from a superior officer in the military before the start of the trial, and that the email "indicated the intent of (the trial) was to seek a prison sentence".

Commander Street told the court that the sentence should be "on the low end of the spectrum", saying that the period of the offences was only about six months and they would not have continued.

"This was not some ongoing clandestine ... scheme to defraud the Commonwealth," he said.

Captain King was seeing a psychologist, he said. His career with the Navy was "patently at an end". But he had a previously good record.

The prosecution did not request any particular penalty but said the panel should bear in mind that the Navy allowance system was based on trust because rorting was easy and detection difficult.

It was therefore important that when an officer of Captain King's seniority was caught exploiting the system, he should be adequately punished as a deterrent to other defence force members.