But a forensics expert has also told a court that DNA tests of the woman's clothing produced information which was either insufficient or too complex to make a match with the alleged offender.

Geoffrey William Joyce is currently on trial in the ACT Supreme Court over a sexual assault that allegedly occurred in March last year.

Joyce, then 30, was on leave from his base in Darwin, and was in Canberra to meet up with friends, after plans to visit regional NSW fell through.

He started drinking in the afternoon at a game of baseball in Narrabundah and then went out to Civic for a night out.

In the early hours of the morning, he came across the alleged victim, and asked her if he could use her phone charger to charge his phone.

The pair walked to the woman's nearby hotel room on Northbourne Avenue.

The Crown then accuses Joyce of pushing the woman to the bed, and raping her.

He is accused of pinning her to the bed, and at times grabbing her throat, and telling her to "stop f---ing crying".

But Joyce denies the crimes, saying the pair never had sex.

He claims he became uncomfortable and left the room when the woman took her pants off and made a suggestive remark.

The ACT Supreme Court heard evidence on Thursday from an Australian Federal Police forensics expert.

She told the court that a mixed DNA profile of Joyce and the complainant had been found on a sheet wrapped around the bed's doona.

That DNA was 80 quadrillion times more likely to be Joyce and the complainant than two random people.

But Joyce has not denied being in the room, and the expert said that samples taken from the woman's jeans, underwear and bra were either too complex, or produced insufficient information, to make a match.

Joyce was also excluded as a match from a number of samples taken from the clothing.

Medical swabs and smears were also taken from the complainant, and they failed to find any saliva or semen.

The trial continues before Justice Hilary Penfold on Thursday afternoon.