A senior Navy officer accused of repeatedly groping a subordinate was "a fundamental betrayal of the trust that must exist between men and women that serve in a modern defence force", a court has heard.

The court martial regarding the allegations began on Monday at Devonport Naval Base after an incident at the base's bar following a dinner on the HMNZS Canterbury on May 17, 2012.

The commander is charged with the indecent assault of a female lieutenant, whom he had known for more than a decade.

Both have name suppression.


The complainant claims the high-ranking officer grabbed her buttocks up to five times over the course of the evening in question.

But defence counsel major Peter Brock said that was completely denied by the defendant.

"He did not grab her, or slap her or touch her on the buttocks," he said.

"Someone may have; he doesn't know that. But it wasn't him."

On the night in question, the commander was responsible for the smooth running of the function and was responsible for looking after other military top brass in attendance.

Major Brock said the allegations therefore made no sense.

"It's patently implausible a senior member of the Navy . . . and host of a VIP would do something like this," he said.

The lawyer reminded the court that the woman had not seen an arm moving towards or away from her rear, so could not be sure the commander was the culprit.

No one else had witnessed the alleged indecent assault either, he said.

"[The lieutenant's] perception and cognition and perhaps her visibility have been impaired by alcohol. She has misconstrued the circumstances," Major Brock said.

"A mistaken witness can be a very credible witness, because they're convinced what they're telling you is the truth."

Prosecutor Chris Griggs, during his closing, said the case was "about a failure of leadership and comradeship".

"It's about a senior officer . . . who abused his authority who indecently assaulted a junior officer at a social event."

Mr Griggs accepted the nature of the assault was at the lower end of the scale but it was significantly aggravated by the alleged repetition of the act and the disparity in rank.

"The accused's actions were a fundamental betrayal of the trust that must exist between men and women that serve in a modern defence force," Mr Griggs said.

"It strikes to the heart of what it means to be a leader."

At the start of the week the lieutenant told the court about what happened in the bar.

"The first one was quite a deep feel. The other smaller ones were pinches I guess," she said.

She told the court she was sure the defendant was the one responsible.

"There wasn't anybody else behind me . . . there wasn't anybody else that acknowledged I turned around," she said.

"I said 'hey' . . . he gave me a sly look back and a laugh."

Mr Griggs said the commander was the only one in close proximity and it was "simply not plausible" to suggest it could have been someone else.

But when the defendant gave evidence yesterday, that was exactly his suggestion.

"His case is he did not grab her by the buttocks, or slap her on the buttocks or pinch her," his lawyer major Peter Brock said.

"He doesn't say she's made this up but he does say she's made a terrible mistake."

Mr Griggs said the case was "a classic he said, she said" but questioned why his client would lie.

"On the evidence, it's quite clear the lieutenant has absolutely no reason to say it was the commander if it was not; quite the contrary," he told the court.

"It's taken a lot of courage for her to come forward and give evidence before you this week."

Judge Charles Blackie will sum up the case before releasing a panel of three military members to consider its verdict.