Former school teacher Chris Dawson is facing a new charge of carnal knowledge with a girl, related to his time as a teacher on the Northern Beaches in the 1970s and ’80s.

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.

Mr Dawson has denied murdering his first wife Lynette.

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

NSW Police said it had charged a 70-year-old man with “carnal knowledge teacher of girl between the ages of 10 and 17”.

The ABC understands that man is Chris Dawson.

Detective Superintendent John Kerlatec said police had undergone an “exhaustive” inquiry since July last year 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 offended be brought before the court and answers for their criminal actions.”

Police appealed for anyone who might have more information 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.

On Thursday, Mr Dawson’s lawyer Greg Walsh told the court that he and prosecutors had mutually agreed to a five-day window for a committal hearing on the murder charge in February.

-ABC