The man, who has interim name suppression, appeared for court-martial on Monday at Burnham Military Camp, 30km south of Christchurch, for a trial that is expected to take one week.
He admitted to pouring a can of Red Bull over the complainant before slapping the woman across the face in June 2017.
He denied the second charge of slapping her in the face and sexually violating her in a hotel room in July 2017.
The officer is charged under the Armed Forces Discipline Act 1971 and Crimes Act 1961 and appeared before Judge Kevin Riordan and a panel of military members.
During the military prosecution’s opening submissions, prosecutor John Whitcombe said the officer poured the Red Bull over the complainant and slapped her before backing her up against a wall.
He allegedly called her degrading names and told her it was what she deserved.
Whitcombe said later that day the officer messaged her: “My dad taught me if I ever hit a woman I’m a coward but I guess that’s true but I still hate you for what you did”.
A month later the pair agreed to meet up at a hotel overseas for a sexual encounter.
The officer gave the complainant instructions such as what to wear and how the hotel room should be laid out, the military prosecutor said.
He messaged her in the days leading up to the encounter saying it was not his intent to leave her “bleeding and in pain” but that she upset him and he needed to let some anger out. They also discussed a safe word.
“You need to be prepared to not tell me to stop... I’m likely to slap you hard and be rough... You don’t need to be scared of me because I’m not a dangerous person.
‘You f***ed me up and I need to let it out.”
On the night of the encounter, the officer allegedly sent more messages to the complainant, telling her she is “f***ing disgusting and that will never change”.
He allegedly told her he didn’t want her to use the safe word unless she really needed to and if she did, he would become angry and leave.
“You should be f****** nervous... good luck sl**. You’re going get what you deserve,” he allegedly told her prior to meeting up.
The complainant arrived first and waited for the officer in the hotel room.
When he arrived, he allegedly walked up to her and without warning slapped her forcefully across the face, causing her vision to go blurry.
She began to cry and her face became swollen, the military prosecutor alleged.
The prosecutor claimed that the slap went beyond what was agreed between the pair.
The officer continued to slap the complainant throughout the evening while using abusive language, the prosecutor claimed.
At one point during the sexual encounter, the complainant tried to pull away but the officer allegedly wouldn’t let her.
When she was able to pull away eventually, she began crying again and ran to the bathroom to vomit, the prosecutor said.
A few days later the complainant sought medical treatment for her swollen face, telling medical staff the swelling was due to a new mascara she had tried.
She laid the complaint about the alleged assault in 2018.
The officer said that everything that happened in the hotel room was consensual and he did nothing wrong.
The trial continues.
