Rewards of up to $500,000 are being offered for information that leads to successful prosecutions in five unsolved Canberra homicide and missing persons cases dating back more than 50 years.

The ACT government has announced the rewards for the cases of Keren Rowland, Elizabeth Herfort, Megan Louise Mulquiney, Troy Hugh Forsyth and David Abuoi, also known as Gabrielle Malak Arok.

Ms Rowland was 20 when she disappeared on February 26, 1971, after attending the Royal Canberra Show. Her remains were found at the Air Disaster Memorial almost three months later.

Ms Herfort was last seen at the Australian National University Bar in Acton on June 13, 1980, while 17-year-old Ms Mulquiney disappeared after being seen outside Woden Plaza on July 28, 1984.

Mr Forsyth, 17, was fatally struck by a panel van while walking with friends along Kent Street, Deakin, on March 1, 1987. Police never located the vehicle or its driver.

Mr Abuoi was 35 when he was last seen in Civic on July 10, 2012. Police suspect he was murdered.

Police say three of the five matters remain classified as long-term missing persons cases, but anyone whose information establishes that criminal activity was involved could be eligible for a reward.

Police, Fire and Emergency Services Minister Marisa Paterson says the rewards are intended to encourage people with information to come forward.

“The families of these five people have never given up hope of getting answers regarding what happened to their loved ones. Half a million dollars is a strong incentive for someone to tell police what they know,” she says.

Chief Police Officer Scott Lee says the five cases were identified by the Unsolved Homicide and Long-Term Missing Persons Team as those most likely to have witnesses or information that could assist investigators.

The five rewards are in addition to those previously offered over the unsolved murders of Kathryn Grosvenor in 2002, Susan Winburn in 2004 and Frank Campbell in 2005.

Anyone with information is urged to contact police via the Crime Stoppers ACT website.

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