The High Court rejected Roger Rogerson's leave for appeal after Chief Justice Susan Kiefel said there was no reason to doubt the decision of the NSW appeals court.

The outcome, almost a decade after the cold-blooded execution of Sydney drug dealer Jamie Gao, finally puts paid to the glimmer of hope the former rogue detective may have held of eventual release and closes one of the darkest chapters in the nation's policing history.

Rogerson's lawyers argued his inability to adequately cross-examine co-accused fellow former detective Glen McNamara hurt his case.

Both men were jailed for life in 2016 over the slaying of 20-year-old Gao two years earlier.

Rogerson, 82, argued his innocence, saying he was unaware of McNamara's plans.

His lawyer, Madeleine Avenell SC, said the cross examination was beyond simply discrediting McNamara as a witness.

She said the defence had been stripped of the chance to prove McNamara, 64, had it in for Rogerson and was determined to implicate him in the murder.

"It's beyond just a 'don't accept this person's evidence'," she told the High Court on Friday.

"The inability to cross examine gave rise to a miscarriage of justice."

The Crown argued the case didn't rely on McNamara's evidence to prosecute Rogerson, instead relying heavily on CCTV footage.

Sally Dowling SC asked the judges to look at the strength of the prosecution case, which they determined was strong enough to strike out the appeal.

The NSW Court of Criminal Appeal previously concluded Rogerson's case for overturning his conviction was "completely lacking in credibility and did not raise any doubt about his guilt".

Both hero and villain during a 28-year NSW Police career, Rogerson was at one time considered the force's most decorated officer.

The culmination of his recognition was to receive the coveted Peter Mitchell Award for outstanding police work in 1980 but within six years, his career had unravelled spectacularly.

In 1981 he was controversially found responsible for the fatal shooting of another young drug dealer, Warren Lanfranchi, but deemed to have acted in the line of duty.

However Lanfranchi's girlfriend, sex worker Sallie-Anne Huckstepp, soon after alleged Rogerson deliberately killed him over a drug-related dispute involving corrupt police. Huckstepp, herself, was later found drowned and her murder remains unsolved.

At the peak of Rogerson's demise, he was also implicated in the attempted execution of NSW undercover operative Michael Drury after the similarly decorated drug squad detective declined to accept a bribe in exchange for evidence tampering in a heroin trafficking trial.

Drury was shot twice through his kitchen window on Sydney's north shore. Rogerson was charged and eventually acquitted of the attack in 1989 but by then had already been drummed from the force for depositing $110,000 in bank accounts under a false name.

Richard Roxburgh portrayed Rogerson in the 1995 mini-series Blue Murder and its 2017 sequel Blue Murder: Killer Cop.

Australian Associated Press