As the manager of Australian rock royalty AC/DC, Crispin Dye had already travelled the world enjoying the trappings of international music success.

The 41-year-old, himself an accomplished pianist and guitarist, then decided to strike out on his own, releasing an album that had begun to capture widespread air time on Australian radio stations in 1993.

Dye was out with friends in Surry Hills and Darlinghurst celebrating the success of that album when, in a lane near Taylor Square, his fledgling career was cut short.

Dye was brutally bashed, robbed and left lying unconscious in Little Oxford Street. He died two days later - on Christmas Day, 1993 - in St George Hospital in Sydney.

Dye's three attackers, all thought to be in their teens or early 20s, were never captured. A coronial inquest was held in 1995, but no charges have ever been laid. 

Now, the state government is offering a $100,000 reward for information leading to the arrest and conviction of those responsible for his death.

"There are people out there who know those responsible for Mr Dye’s death and we’re hoping this reward may prompt them to get in touch with police,” Detective Superintendent Mick Willing, the commander of the Homicide Squad, said.

“By all accounts, Crispin Dye was a fun-loving, friendly and decent man, who was robbed of his life far too soon.

“We are absolutely committed to getting to the bottom of this case and bringing those responsible for an innocent man’s violent death to justice, but we won’t be able to do it without assistance from the public."

Dye had spent seven years managing AC/DC, in which he helped the group become one of the world's biggest rock bands.

A gold record he received for his work on the band's 1985 album, Fly on the Wall, hung in the lounge room of his winter home in Cairns at the time of his death. He lived the remaining half of the year with his mother in Willoughby.

Dye was also involved with the hard rock band Rose Tattoo, and had worked with the former Easybeats and famed Australian songwriters Harry Vanda and George Young, and with such artists as Jon English, Doug Ashdown and Margret Roadknight.

On the night of his bashing, on December 23, 1993,  Mr Dye had been out with friends following the release of his first album, A Heart Like Mine, which he released under the stage name Cris Kemp.

He had left Gilligan's nightclub at Taylor Square about 1am to go to the nearby Flinders Hotel.

He was last seen there about 3am before going to the Courthouse Hotel, where he was refused service by bar staff shortly after 4am. He was found unconscious in Little Oxford Street about 4.35am suffering major head injuries.

A witness told police he saw three teenagers standing over Mr Dye and rifling through his wallet as he lay bleeding in the dark lane, before they ran north towards Goulburn Street.

Police described the men as being of Pacific Islander appearance and aged in their late teens or early twenties. Two of the men were wearing baggy long pants and T-shirts, while the third man was dressed in baggy knee-length shorts, a white T-shirt, joggers with white socks and a dark baseball cap.

Police Minister Stuart Ayres said Mr Dye’s family and friends had been suffering for more than 20 years.

“It’s now been more than two decades since Mr Dye was killed, and yet his poor friends and family still don’t know who is responsible,” Mr Ayres said.

“We know detectives are doing everything they can to solve the case, and we are hopeful that this $100,000 reward offer will help them in their pursuit of Mr Dye’s killers."

Police have urged anyone with information to contact Crime Stoppers on 1800 333 000 or visit the Crime Stoppers online reporting page.