Despite the years rolling on, his family have never lost hope that he is alive.

Police have renewed an appeal for any information about the former Wollongong metallurgist, pleading that his family needs closure.

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"It's OK, Grant ... you don't have to come back to this area if you don't want to but please just make contact with Crime Stoppers for the sake of the rest of your family," said Detective Senior Sergeant Clem Scott, Investigations Manager at Lake Illawarra Police District.

"They're in pain every day, they need some sort of closure. Unfortunately your mother passed away, she never got to say goodbye, she never got to know the result of whether you're alive or not."

Mr Rodgers is one of a handful of long-term missing person cases for the Lake Illawarra District, although authorities have never given up investigations.

Although the then 29-year-old's 4WD was discovered at Mount Kembla following his disappearance, a coroner's report found there was "every opportunity that he was still alive".

"We know that he had a high pressure job at the time he went missing, but it was out of character to go missing and to leave his loved ones in that way," Detective Senior Sergeant Scott said.

"[His sister Jane Neville has] provided some information over the years and that's led us in a few different directions both around this area and also interstate.

"But everything we've tried so far we've come up short, we've got no confirmed sightings of him for 30 years. But she's still holding onto that hope that he's out there somewhere."

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Ms Neville described her pain over the years as sadness, frustration, anger, fear and a great sense of loss.

"It has been pure torture," she said. "What makes me keep going is best case scenario, that somewhere out there he's happy, he's got a great life, possibly a life he couldn't have before he disappeared."

Detective Senior Sergeant Scott said there had been a review of how missing persons operations are conducted in NSW to improve outcomes for loved ones.

This has included increasing the reward money offered on information for some cases, and the use of a new targeted SMS system adapted from a tool used during bushfire emergencies.

Detective Senior Sergeant Scott said Illawarra authorities were looking into the use of the geo-specific messaging tool, which has been in operation in other regions since March.

It sends a text message to mobile phones within a specific geographic area describing the missing person and including a link to their image, the texts will always come from the same mobile number, +61 444 444 444.

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Anyone with information about Mr Rodgers' disappearance is urged to contact Crime Stoppers on 1800 333 000.

There are currently 239 NSW Government rewards on offer to find missing people with two more increased rewards of $1 million each being announced this week.

The vast majority of people reported missing are found by police within the first 24 hours, but there are long-term cases that remain open and under investigation and regularly reviewed.

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