She was supposed to meet her mother for lunch in Northbridge Baths in Sydney, but she never arrived.
More than 30 years later, police are offering a $200,000 reward in a bid to solve the mystery of what happened to mother-of-two Lynette Joy Dawson.
The 33-year-old who had "so much to live for" was last seen on January 9, 1982, police say.
The night before she vanished, Mrs Dawson was at home with her husband Christopher Dawson in Sydney's northern beaches when she called her mother.
The pair agreed to meet for lunch at Northbridge Baths in Sydney the following day.
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She was officially reported missing on February 18, 1982 by Mr Dawson.
Detective Sergeant Damian Loone who is leading the investigation believes Mrs Dawson was not responsible for her own disappearance.
"At the time of her disappearance, Lynette was the loving mother of two daughters - a two-year-old and a four-year-old," Det Sgt Loone said in a statement on Thursday.
"She was also extremely close to her parents and three siblings.
"We think it's highly unlikely that Lynette staged her own disappearance. She had so much to live for."
Police believe there are people out there who know what happened to her but are either afraid or unwilling to share that information with officers, he said.
"If you know where she is, or what has happened to her, please give us a call.
"We don't need to know who you are; all we need is the information you have to hand."
Minister for Police Michael Gallacher said Mrs Dawson's family had been suffering for 32 years.
"To this day, her now-adult children have no idea where she is or why she never came home," he said.
"Lynette's loving parents died without ever knowing what happened to their daughter."
In 2010, the NSW government announced a $100,000 reward for information leading to the arrest and conviction of those responsible for Mrs Dawson's disappearance.
The state government on Thursday announced the reward would be doubled for information leading to the arrest and conviction of those responsible for the disappearance and presumed murder of Mrs Dawson.
