Chris Dawson, the subject of The Teacher's Pet podcast, is facing a new charge of carnal knowledge with a girl, related to his time as a teacher on Sydney's northern beaches in the 1970s and 80s.

Key points: Chris Dawson is the subject of The Teacher's Pet podcast

Chris Dawson is the subject of The Teacher's Pet podcast The charge of "carnal knowledge" no longer exists

The charge of "carnal knowledge" no longer exists However, it relates to having sex with an underage person

Earlier on Thursday Mr Dawson faced Sydney's Downing Centre Local Court where he formally entered a not-guilty plea to a charge of murdering his wife Lynette, who went missing 37 years ago.

The case received global attention in the popular podcast, by journalist Hedley Thomas, which is temporarily unavailable for download, pending Mr Dawson's trial.

Hours after his not-guilty murder plea, NSW Police said they had charged a 70-year-old man with "carnal knowledge teacher of girl between the ages of 10 and 17".

Detective Superintendent John Kerlatec fronts the cameras in Surry Hills. ( ABC News )

Detective Superintendent John Kerlatec said since July last year police had carried out an "exhaustive" inquiry that had included statements from several witnesses.

"It's a very serious charge, it does relate to a 1980s charge, hence [the use] of the term carnal knowledge," he said.

"The investigation covers a broad geographic area and a lot of people have come forward already.

"We seek to find justice for each and every victim and ensure the person [who] offended be brought before the court and answers for their criminal actions."

Police appealed for anyone who might have more information about the case to come forward.

Mr Dawson was charged last year with Lynette's murder, more than three decades after the mother of two vanished from their northern beaches home.

Her body has never been found and Mr Dawson has always denied having anything to do with her disappearance.

Mr Dawson's lawyer Greg Walsh told Sydney's Downing Centre Local Court that he and prosecutors mutually agreed to a five-day window for a committal hearing over the murder charge in February next year.

"That's sort of stretching the friendship isn't it," Deputy Chief Magistrate Michael Allen responded.

Lynette and Chris met at a high school function, both aged 16. ( Supplied )

Mr Dawson's lawyer Greg Walsh told the court a clairvoyant worked with Mr Thomas in interviewing witnesses for the podcast.

Outside court, Mr Walsh handed the media copies of a photograph showing Mrs Dawson's sister consulting a psychic medium and a detective.

"Anybody using their common sense would say, 'Why would police be utilising someone who's using tarot cards?'," he said.

"It just defies belief."

The court heard prosecutors and Mr Walsh have so far agreed on a list of eight witnesses to be examined during the committal.

They include Thomas and a 100-year-old woman who claimed to have seen Lynette after she was said to have vanished.

Crown Prosecutor Craig Everson said there was a large volume of material on The Australian's website that was contained in the brief of evidence and the newspaper had agreed to remove it.

"The trial in this context is almost uncharted waters, historically," the judge said.

Last month, a Sydney Court heard "vitally important" material relating to the case against Mr Dawson may have been shredded.

Mr Walsh said the material believed to have been shredded was collected by journalist Hedley Thomas for the podcast.

Mr Dawson, a former PE teacher and Newtown Jets rugby league player, attended the hearing but did not make any comment outside court.

The matter was adjourned until August.