Jamie Weaver was convicted of assisting her partner Miroslav Jovanovicwho had stabbed a man, with the intention of helping him to escape being caught or prosecuted. She was convicted following a trial by judge alone in the ACT Supreme Court last week.

Jovanovic was sentenced in May to 10 years and nine months in jail, with a non-parole period of 5½ years, over the attack at the Belconnen bus interchange in April last year.

Weaver was present when he used a knife to stab the victim.

The Crown had alleged Jovanovic passed Weaver the knife, she put it in her bag and must have disposed of it because it was never found.

She later told police she had no knowledge of a knife or any weapon, according to the Supreme Court judgment published on Friday.

At trial, her defence argued the prosecution case was circumstantial and had not excluded the "rational hypothesis" that, after the assault and before his arrest, Jovanovic disposed of the knife in a "blind spot" not visible on CCTV footage and a third party took the knife before police searched the area.

Chief Justice Helen Murrell found Weaver lied to police when she said she had no knowledge of a knife.

"As the Crown submitted, she was at 'point-blank' range when the assault occurred," Chief Justice Murrell said.

"The CCTV footage shows that she arrived on the scene very soon after the commencement of the assault. The complainant (and two eyewitnesses) all saw the knife and were able to describe it in some detail.

"As the accused was prepared to lie to police concerning the assault and her knowledge of the knife, I conclude that other important parts of the version that she provided to police may be completely unreliable."

Chief Justice Murrell said Weaver lacked credibility and had lied when she gave evidence in Jovanovic's trial "to the effect that she recalled him passing cigarettes to her as the couple walked away from the scene of the assault".

"It must be inferred that the accused was concerned about the involved of her partner, Mr Jovanovic, and was particularly concerned about the fact that he used a knife," Chief Justice Murrell said.

"When she received the knife, I find that she intended to assist Mr Jovanovic ... by the removing the knife from his possession. She intended to conceal or dispose of it.

"Consistent with that intention, she did in fact conceal or dispose of the knife and that is why it was never found."

Chief Justice Murrell also found Weaver deliberately lied about the passing of the cigarettes and her motive was to "cover up Mr Jovanovic's involvement in the offence and incidentally to conceal the accused's own involvement".

"I am satisfied the accused lied both because she had a guilty state of mind in relation to the offence and because she wished to protect Mr Jovanovic; these motives are inseparable," she said.

Weaver will face court on October 10 for a sentencing hearing.