Police have upped the reward – previously $100,000 – in a bid to flush out new information on the 1994 killing.

Mr Beer died while slashing grass at his rural Tallandoon property on Lockharts Gap Road on February 6, 1994.

His body was found slumped over his tractor by a passing friend the following day.

It was initially thought he had died of a heart attack, but a bullet from a high-powered rifle was found lodged in his chest.

The reward has been increased to coincide with the screening of Prime7 show Million Dollar Cold Case on Wednesday night.

Mr Beer had been involved in a long-running dispute with his neighbour David Supheert before his death.

Detective Inspector Phil Shepherd said Mr Supheert, who lived on the other side of the road, had not co-operated with police.

“At no stage have we had any explanation from David Supheert about what he was doing leading up to and at the time of David Beer’s murder,” he said on the show.

“He’s never provided us with an explanation as to what his activities were on that day.”

The murdered man’s son, Wayne Beer, said a conviction would help ease the family’s lingering pain. 

“There is somebody out there who knows something we can take to court,” he said. 

“It only needs to be something small, then they will be brought to justice. 

“Hopefully with this $1 million, it will encourage them to come forward and help us.”

The hardest part, Mr Beer said, was knowing the killer was out there "getting away with it” and “enjoying a wonderful life".

“My father never got the chance to see his granddaughter grow up,” he said. 

“He never got a chance to be so proud of his daughter. 

“He's missed out on so much. 

"The person who did it has missed out on nothing.”

Detective Inspector Shepherd hopes the money will get people talking. 

Anyone with information can call 1800 333 000.