Police have released forensic artist impressions of the men in an effort to help solve the 2002 crimes.
A $1 million reward had already been on offer for information that led to the conviction of anyone responsible for the suspected murders of Iain Hogg and Frederick Hugh Rosson.
Police are again appealing for information after receiving new information, resulting in the computer-generated facial composite images.
Detective Sergeant Scott Chapman said police hoped the images would prompt people to come forward.
"We are asking the community to take a moment to look at these images," he said.
"Twenty-four years have passed and relationships and loyalties change.Â
"People who may once have been afraid to speak may no longer feel that way. It is never too late to come forward."
Mr Hogg, 45, was reported missing on March 12, 2002, by his mother after he failed to attend his workplace as a manager of a Gold Coast liquor store the previous day.
His red 1992 Toyota Celica coupe, with Queensland registration 861GBW, was also reported missing.
Witnesses have told police that between 1am and 3am, Mr Hogg's Celica was parked near a pontoon at Tweed Heads.
Witnesses saw a number of people around the vehicle, then a flash followed by a loud bang, believed to be from a firearm discharging.
It is believed Mr Hogg's body was dumped in the river.
On March 14, 2002, Frederick Hugh Rosson, aka Charles "Slim" Johnson, 67, was fatally shot at his home in Mount Nathan on the Gold Coast hinterland.
Investigators believe Mr Rosson was attempting to sell a 9mm CZ handgun and ammunition, which were stolen.
Witnesses have told police they saw two men driving a red Celica which visited Mr Rosson at the time of his murder.
On March 20, Mr Hogg's car was found abandoned on 15th Avenue at Palm Beach.
Subsequent investigations forensically linked the vehicle to both crimes.
Investigators believe Mr Hogg and Mr Rosson were not involved in any criminal activity and had no known association to each other.
Following a renewed public appeal in 2024, police received new information over the identities of two men similar in description to two images created from witness accounts in 2002.
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