John Chardon appeals child sex convictions

Three Queensland judges have reserved their decision on a legal appeal by Gold Coast man John Chardon against his convictions for child sex offences.

Chardon, 67, is the husband of Novy Chardon, who has been missing since February 2013.

He was sentenced to six years' imprisonment last August after a jury found him guilty of molesting and raping a teenage friend of his daughter in 1998 and 1999.

Chardon's lawyers challenged the verdicts in the Court of Appeal in Brisbane on Tuesday.

Justices Margaret McMurdo, Robert Gotterson and David Jackson reserved their decision.

Earlier, Chardon's barrister Anthony Kimmins argued the convictions were against the weight of evidence, and the judge at his trial failed to adequately put the defence case to jurors.

Mr Kimmins said there were issues with the credibility of the complainant - who was 14 when the abuse allegedly started - which the judge had only dealt with as an afterthought.

"The fact is there are glaring inconsistencies in relation to what she said," Mr Kimmins said.

"She has a different tale from virtually every other witness who gave evidence in the trial."

However barrister Ben Power, for the Crown, said the jury had been strongly warned about the reliability of the complainant's evidence, and that mistakes in her recollection more than 10 years on didn't mean her whole story was unreliable.

"They were entitled to find her to be a truthful and reliable witness," he said.

Chardon, who was not in court, has abandoned an appeal of his prison sentence.

Police investigating Novy Chardon's disappearance believe she was murdered.

Chardon has previously been named as a person of interest but denies involvement and has never been charged.