The prison guard was accused of raping and seriously assaulting his ex-partner in Canberra several years ago. The pair were locked in a bitter property dispute at the time the allegations were made, and their break-up had been far from amicable.

But a flawed police investigation into the allegations saw the man charged and eventually remanded in custody, despite evidence that should have cast doubt on what she was saying.

The man, who was a prison officer at the Alexander Maconochie Centre, was sent to Goulburn jail, in an attempt to protect him from inmates who would target him due to his job.

He spent four months behind bars in Goulburn, and has spoken of having to invent back stories, and of his constant fear that his fellow inmates would find out he was a screw.

Eventually criminal investigations detectives were brought into the case, and became suspicious when the woman started making allegations against her ex's family, saying they harassed, intimidated, burgled and bugged her

She was put under surveillance, which made it clear to police she was inventing claims against her ex's parents.

The prison guard also had an alibi for the alleged rape, which prosecutors were not told of immediately.

He was released, the charges were dropped, and instead his accuser was herself put on trial.

She faced charges of making false accusations, and was found guilty in August in the ACT Magistrates Court.

The woman appealed her conviction, but prosecutors tried to have the appeal thrown out in the ACT Supreme Court recently.

They argued that the appeal was "incompetent", because the woman had not actually been convicted by the magistrate.

When the magistrate made her finding, she said only that the offences had been proved, not that the woman was convicted.

That was done by Chief Magistrate Lorraine Walker so that she could have the option of making a non-conviction order when sentencing the woman.

But prosecutors argued that because the magistrate had not actually convicted the woman, her legal team could not appeal a conviction.

Chief Justice Helen Murrell dismissed that argument on Friday afternoon.

She said that the magistrate, by finding the offence proved, had made a conviction.

"A finding by the Magistrates Court that an offence has been proved [a finding of guilt] is a 'conviction'," Chief Justice Murrell wrote.

"The word 'conviction' has no 'ordinary meaning'. Depending on the context in which it is used, it may refer to a finding of guilt, to the formal recording of a conviction or to the finalisation of criminal proceedings by the imposition of a sentence."

The appeal will be allowed and will return to court next week.