This morning Dawson was arrested at the home of his twin brother on Queensland's Sunshine Coast.
Speaking on the arrest, Detective Chief Inspector Chris Olen said: "A 70-year-old man has been arrested this morning shortly before 8 o'clock in relation to the murder of Lyn Dawson".
An Australian man has been arrested after a podcast shed new light on the disappearance of his wife 36 years ago.
Days after her disappearance her husband Chris moved his schoolgirl lover into the family home.
NSW Police Commissioner Mick Fuller said the brief of evidence would rely mostly on information discovered by police, but confirmed media interest in the case had resulted in new evidence.
Mr Dawson told Lynette's family that she needed time away, and he did not report her missing to police for nearly six weeks.
Mr Dawson is due to appear in Paramatta Local Court on Thursday.
The Commander of the NSW Homicide Squad, Detective Superintendent Scott Cook, said Mr Dawson was "calm" but "taken aback" when he was taken into custody.
Dawson has always maintained his innocence, and claimed his wife had run away to live with a religious cult in remote area of NSW.
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Her body has never been found and two coronial inquests, between 2001-2003, found Ms Dawson was murdered by her husband.
In a statement, the police said: "In 2015, detectives from the Homicide Squad's Unsolved Homicide Unit established Strike Force Scriven to re-investigate the circumstances surrounding her disappearance and suspected murder".
Police allege Mr Dawson was in the process of divorce from his wife and he was having an "illicit affair".
Ms Dawson was 33 when she went missing from the northern beaches in 1982, leaving behind two daughters.
A forensic search of the home the Dawsons once shared in Bayview was undertaken.
"I wouldn't have written to the DPP otherwise", he said. We have solved homicide before without identifying the body.
"Without a body, without knowing first of all whether in fact she is dead, without knowing secondly if she is dead, how she died, it's very hard to mount a case of a reasonable prospect of conviction just on motive and the undefined existence of means and opportunity".
He said two witness statements in particular helped piece the evidence together.
"We have no doubt whatsoever that Chris will be found not guilty as he is innocent".