An Australian teacher has been found guilty of murdering his wife 40 years ago while having an affair with his teenage student.

Christopher Dawson, 74, was convicted in the judge-only trial of killing wife Lynette in January 1982, after the hit true crime podcast series Teacher's Pet triggered renewed public interest in the case.

A 2003 inquest had recommended charging Christopher Dawson with his wife's murder but prosecutors declined, citing a lack of evidence.

Australian teacher Christopher Dawson has been found guilty of murdering his wife 40 years ago while having an affair with his teenage student

oday, Supreme Court judge Ian Harrison found Dawson deliberately killed his wife to pursue a relationship with a teenage student he was having an affair with, known as JC, and who had babysat and lived in his Sydney home.

Dawson maintained his wife had left him and subsequently telephoned him to say she needed space, but the judge called his defence fanciful and riddled with lies.

The judge noted there was no record of Lynette contacting family or friends since her disappearance, nor of making credit card payments or working.

Dawson's lawyer, Greg Walsh, told reporters outside court that his client would appeal the conviction.

Police charged Dawson with Lynette's murder in 2018, four months after the final episode of Teacher's Pet, which criticised the law enforcement response to her disappearance and featured multiple witness interviews.

Harrison, the judge, noted that the case against Dawson had been wholly circumstantial since Lynette's body had never been found and there was no known cause, location or exact time of death.

But the combination of small pieces of evidence, including inconsistencies in Dawson's defence, was persuasive and compelling, he said.

'I am left in no doubt, I am satisfied beyond reasonable doubt, that the only inference is that Lynette Dawson died ... as a result of a conscious and voluntary act by Mr Dawson with the effect of causing her death.'

When police reopened their investigation they said only that it was because new witnesses had come forward, but media reports said law enforcement sources confirmed they were motivated by publicity generated by the Teachers Pet, which has been downloaded 30 million times.

Dawson's defence argued that the podcast, produced by News Corp's The Australian newspaper, denied him a fair trial because of the way he was depicted.

Harrison agreed the podcast had cast Dawson in a negative light but said he did not factor that into his verdict.

Dawson, who was on bail, was taken into custody.