The conviction of Rhiley Boyson after a court martial earlier this week was the first conviction for sexual intercourse without consent in the military jurisdiction in at least 20 years, prosecutors said.

A panel of five male officers had found Boyson, 26, guilty of the crime on Monday after the five day court martial. After several hours deliberating, on Wednesday they delivered their punishment.

Chief Judge Advocate Michael Cowen QC ordered military police officers take Boyson in custody and escort him to the military prison at Holsworthy barracks in Sydney, pending an automatic review of the sentence.

If the review upholds the sentence Boyson will be transferred to the nearest civilian prison, being Silverwater, NSW. If the review is not complete in one month, Boyson will be released from custody while he awaits the outcome.

While the demotion comes into effect immediately, the jail sentence and the dismissal are pending the review. Boyson also has rights to appeal the conviction.

A sentence hearing at the court martial facility in Fyshwick on Tuesday was told Boyson had been at an army social function in 2017 with the victim, who was a friend and fellow officer.

The group's drunken bathroom horseplay ended with the victim in a vulnerable position on the floor frantically trying to pull his pants and underwear up.

Boyson inserted a beer bottle into the man’s anus in an incident that lasted a few seconds.

In sentencing Boyson, the panel had been guided by submissions from prosecuting officers, defence officers and the judge advocate.

Prosecutors referenced former Chief of Army Lieutenant General David Morrison’s now famous 2013 speech “the standard you walk past is the standard you accept”.

They said though the offence was the result of a prank gone too far the behaviour was unacceptable.

Defence officers called it a moment of madness and an aberration, an "act of tomfoolery gone too far".

Boyson had joined the army at 17 and flying was his life, they said when addressing the consequences of his conviction.

The panel had to consider the usual sentencing purposes including of general deterrence, specific deference, denunciation, rehabilitation and recognition of harm to the victim.

Unique to the military is the need to maintain service discipline as a purpose of sentencing.

Also unique is that the same panel, made up of fellow and more senior officers up to brigadier, that found Boyson guilty determined the punishment.

But the rarity of the conviction posed its own challenges at coming to Boyson’s sentence.

There appeared very few if any sentences handed down by military or civilian courts in the past that were comparable.

But the cases were canvassed in court in any event as an example of how similar - in the sense the offenders were charged with rape or acts of indecency - had been punished.

There was the 2011 general court martial of a lieutenant commander of the Navy who was found guilty of seven counts of indecent assault.

He would order a junior officer to lay on his lap while he spanked her bare bottom in a gross breach of trust and authority that went on for months. He was demoted, sacked and jailed for 18 months.

Another case in a restricted court martial earlier this year saw a warrant officer charged with multiple acts of indecency after he exposed himself and showed a woman a video of him having sex with someone else.

That case also saw an incident with a frankfurter. The warrant officer was fined, demoted, sacked from the defence force and jailed for one month.

Further back, the court heard about a 1991 case in the NSW District Court in which a group of defence members pleaded guilty to acts of indecency after forcibly undressing a fellow member in an initiation ceremony.

They originally were jailed for six months but on appeal that sentence was overturned and replaced with good behaviour bonds.

The court noted that the men had spent two months in prison and their behaviour was part of a tradition that had been tolerated in the past.

The court warned that members were on notice from then that there would be significant consequences to that kind of behaviour.