Shane Geoffrey Barker was shot dead at Campbell Town on August 2, 2009.
Tasmania Police cold case investigators have recently re-examined Mr Barker’s murder, and have upped the reward from $50,000 to $250,000.
Detectives from the serious organised crime division are going over old facts of the case.
Tasmania Police assistant commissioner Glenn Frame said there had been a team of five investigators reviewing the case since November.
Commissioner Frame said police believed they had already interviewed Mr Barker’s killer.
“We know that there are people who have information that could lead to a conviction in this case,” Commissioner Frame said.
“In the passage of time someone’s circumstances and allegiances may have changed and the offer of a life-changing amount of money may be the motivation they need to come forward.
“That kind of money allows a fresh start.
“Of course, technology, DNA capability and investigative best practice have all moved on since 2009 and we think these advances could also provide further evidence.”
Anyone with any information can contact Crime Stoppers on 131 444.