Chris Dawson Charged With 'Carnal Knowledge' Of Underage Student

NSW Police have charged former rugby league star Chris Dawson with carnal knowledge of a girl at a Sydney school.

Dawson was arrested by police around 12pm on Thursday, following extensive investigations by detectives.

Strike Force Southwood have been investigating allegations of student/teacher sexual relationships at Northern Beaches high schools in the 1970s and 1980s.

Dawson, 70, was arrested at the Surry Hills police station, and later charged with 'carnal knowledge teacher of girl between the ages of 10 and 17'.

Police said the "very serious" charge related to a 16-year-old girl.

"All sexual assaults are treated very seriously. We seek to find justice for each and every victim, to investigate their matters thoroughly, to ensure the person who offended be brought before the court and answered for their criminal actions," a detective said.

"This has been a very exhausting investigation since July last year. There's been a number of lines of inquiry to follow."

He was granted strict conditional bail, and will face court on August 8.

Earlier on Thursday, in separate court proceedings, Dawson pleaded not guilty to a charge of murder over the death of his wife, Lynette, in 1982.

He was charged in December over the disappearance of his then-wife. His lawyer Greg Walsh formally entered a not guilty plea at Downing Centre Local Court.

The matter is due back before the same court on August 8.

Lynette Dawson's disappearance was the subject of the highly popular investigative podcast series The Teacher's Pet.

More to come.