A violent Sydney murderer who tried to rape a woman at a bus stop while out on parole has been jailed for more than 11 years.

Terrence John Leary, 49, had been on parole for 10 months in June 2013 when he grabbed a random woman returning from work in Hunters Hill, punched her to the ground and tried to sexually assault her.

Judge Helen Syme said the attack was vicious and extremely violent, handing down a minimum sentence of 11 years and three months.

'The attack itself was fast and extremely violent,' she said.

'The viciousness of the attack resulted in immediate terror for the victim and long-term psychological disturbance.'

Judge Syme said Leary had also violently lashed out at police officers who were first on the scene.

Sydney's Downing Centre District Court heard Leary held a dangerous propensity to commit violent offences against spontaneous targets.

In 1990, Leary climbed a window and smashed a 17-year-old girl's skull with a hammer after she spurned his sexual advances.

He served more than 22 years of his 24-year maximum sentence for the murder and was granted parole after six attempts.

Judge Syme said there were clear similarities between the random, sexually-charged and explosively violent crimes.

She said Leary's behaviour was unpredictable and he posed a continuing threat to the community.

'It cannot be said that he has good prospects of rehabilitation,' she said on Tuesday.

Leary will not be eligible for parole until September 2024.

AAP