Bret Walker SC, acting for Ropati Dominic Finau, told the ACT Court of Appeal on Thursday that the Queanbeyan man's conviction should be quashed because of "ineradicable doubt" about his guilt.

Mr Walker said there were "discrepancies and deficiencies" in the young woman's denials that she and Finau in fact had consensual sex, as Finau continued to claim.

Director of Public Prosecutions Shane Drumgold SC, on the other hand, argued Finau's conviction was "a sound conclusion" and that Mr Walker's arguments had "decontextualised" the evidence.

Chief Justice Helen Murrell found Finau guilty of sexual intercourse without consent following a judge-alone trial in June last year.

The incident in question occurred in November 2018, when the offender and the victim, who were casually acquainted through work, bumped into each other on a night out in Civic.

They went together to several nightclubs before sharing a taxi to the Belconnen apartment of the then-18-year-old woman.

Chief Justice Murrell found that Finau, who was 24 at the time, invited himself into the unit on the pretense of having to use the toilet, despite having previously agreed to continue to his own home in the cab.

The judge said Finau attacked the victim once inside, ignoring her resistance to his advances and saying, "I want this, I'm here" before hitting her in the face and sexually penetrating her.

Chief Justice Murrell accepted the young woman's account that Finau only stopped when the victim's cat, which he found "terrifying", jumped onto the sofa bed.

Finau was ultimately sentenced to two-and-a-half years in jail, with nine months of that term to be served behind bars.

However, the man known as "Dom" was released on bail just three weeks after his sentencing, pending the outcome of his appeal.

In court on Thursday, Mr Walker sought to cast doubt on the credibility of the young woman, citing "very large mistakes, or lies" in her early recounts of the incident in question.

He said the teenager had spoken to friends in the aftermath and described things like having felt pressured to share a taxi with Finau because he was in a bad way after being hurt in a fight.

But Mr Walker said the woman had later made the "plain concession" during Finau's trial that he had not been in a fight.

The senior counsel said the then-18-year-old woman had crafted this story of being a reluctant good Samaritan in an effort to lend credibility to her claims that Finau had taken advantage of her and to "squelch any notion of an erotic interest" in him.

Mr Walker also took issue with what he said was "stereotyping without science" in Chief Justice Murrell's trial judgment, with the judge describing Finau's account as problematic and citing the "likely" sexual behaviours of 24-year-old men and 18-year-old women.

Among other things, Mr Walker said Finau did not accept that a cat had been responsible for "the cessation of sexual intercourse".

He said it was strange that the teenager did not mention the "striking detail" of "a detestable cat" apparently interrupting a sexual attack to the friends she confided in a short time afterwards.

Mr Drumgold, however, urged a full bench of the Court of Appeal to uphold Finau's conviction, saying Mr Walker was relying on "reinterpretations of the evidence", which had been "decontextualised".

"The points advanced by the appellant all suffer the same illness," he said.

"There is simply no inconsistency to allow the kind of broad-based rejection of the complainant's evidence that's been suggested."

Using the example of the cat, Mr Drumgold said it was important to note that the animal lived in the victim's apartment.

"Everything that happened in the unit happened with the cat there," he said.

Mr Drumgold argued that it would be "simply incredible" to expect that every time the woman described something that took place in her home, she would tack on, "Oh, by the way, the cat was there".

The Court of Appeal judges reserved their decision.

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