A child sex offender says his convictions should be quashed because the judge at his trial did not warn the jury the victim's evidence could be unreliable. 

But the Crown says such a warning isn't required by law because the defence case argued her evidence was a lie, rather than a result of faulty memory. 

The matter is being argued in the Supreme Court in Wellington this morning, and centres on section 122 of the Evidence Act 2006. 

The legislation allows judges to warn juries the evidence could be unreliable if it has been more than 10 years since the offending happened. 

Gordon John Rippey was sentenced to 16 and a half years in prison in 2017 after being found guilty and convicted on multiple charges of sexual offending. The sentencing judge gave him a minimum non-parole period of eight years and three months. 

The offending happened between 2000 and 2001 when the victim was aged about 10, but police did not lay charges at the time. The charges came in 2015 when the victim decided to do another interview with police. 

In Rippey's trial, the defence was that the victim's evidence was a lie. 

Warning juries on reliability had been "systematically avoided" by trial judges, and the avoidance was "condoned" by Court of Appeal judgements, Lithgow said in his written submissions. 

"The trial judge refused to give the warning even before being asked. She identified, to herself, that it may unnecessarily and unhelpfully highlight the evidence, although how that was so was not explained." 

The judge then justified the refusal on the grounds she was not satisfied the evidence was unreliable, he said. 

The Court of Appeal supported the trial judge's position, saying if the case was about who was telling the truth then it is not about reliability, therefore a warning about the passage of time was not needed. 

But rigid distinctions between credibility and reliability helped nobody, Lithgow said. 

The allegations against Rippey were entangled with a false allegation the victim made against another man. She admitted the other allegation was just a joke, but then went on to tell her parents Rippey had sexually offended against her. 

Her initial police interview in 2001 was also vastly different to her 2015 interview, Lithgow's submissions said. At trial she said she left out a lot of details during her first interview. 

"It can truly be said that the [2015] interview introduced new, more detailed, and more dramatic allegations of sexual misconduct." 

The jury needed to carefully consider whether the victim's memory could have been "embellished" over the lapse of time, he said. 

The lack of warning meant the trial miscarried, and Rippey's convictions should be quashed, he said. 

The Crown lawyers said a reliability warning in the absence of any identifiable risks was at best no help to the jury and at worst "confusing or distracting". 

The Crown submissions said the victim's evidence on central issues at trial was "clear, measured, and unambiguous". 

There was also no indication of embellishment and at times when she was uncertain of her response, the victim provided "appropriate qualification". 

"The judge's reasoning was sound. The allegations were specific," they said. 

"No suggestion had been made that the complainant had been mistaken or misinterpreted the appellant's conduct, or that her memory was faulty due to the passage of time. The defence was one of fabrication and, in general the lapse of time does not have any bearing on whether or not a witness is deliberately giving false evidence." 

Fiona Guy Kidd QC of the Criminal Bar Association, acting as an intervener in the hearing, said even in cases where the defence was "it didn't happen", prejudice could still arise from a long delay in charges being laid. 

Material such as phone records, social media posts and CCTV footage could be lost, the defendant's own memory could fade, Guy Kidd's submissions said. 

"Therefore, even where a defence is 'it didn't happen' there will be prejudice arising from the delay that the jury does not hear about and will not know. 

"This Court's decision must recognise that a complainant or witness may honestly recall a false memory and/or that memories change over time and can be distorted by reinterpretation over time." 

While reliability was a separate issue to forensic disadvantage, the evidence could be unreliable and the defence could be unable to reveal that due to the delay. 

"This approach is necessary as a measure to ensure a fair trial." 

The hearing is expected to last the day and the judges will release their decision at a later date. 

- by Melissa Nightingale, NZ Herald