The son of famous Australian rock star Angry Anderson was killed after a violent assault at a popular Sydney beach on Sunday.

Emergency crews found Liam Anderson unconscious in a park after they were called to Queenscliff in Sydney's northern beaches just after 6am.

The 26-year-old has been identified as the youngest of Angry Anderson's three sons. The lead singer has fronted rock band Rose Tattoo since 1976.

Residents on Pavilion Street and Bridge Road said they heard sounds of moaning coming from the park, located next to busy Freshwater Beach.

Liam Anderson was found unconscious by emergency crews after they were called to Queenscliff in Sydney's northern beaches (pictured)

The son of famous Australian rock star Angry Anderson (pictured: Liam Anderson) was killed after a violent assault at a popular Sydney beach on Sunday

The 26-year-old is believed to be one of Angry Anderson's three sons (pictured Angry Anderson and his family)

Mr Anderson was unconscious and suffering from severe head wounds when emergency crews arrived.

Police said when they arrived they found a 20-year-old man beating Mr Anderson.

Officers confirmed the two men knew each other.

A written note was taped to a bin outside the rock star's Beacon Hill home, asking for their privacy to be respected during the time.

Mr Anderson's manager, Scot Crawford, released a statement on Sunday, explaining the family asked their privacy be respected.

'Following the death of Angry Anderson’s son Liam in Sydney in the early hours of Sunday morning November 4, 2018, the family has asked that media and the general public respect their privacy,' the statement read.

'With the matter in the hands of NSW Police, the family will not be making any comment at this stage, nor are we as Anderson’s management in a position to offer any comment on their behalf.'

Detective Inspector Michael Boutouridis said the 20-year-old man was violent and resisted officers when they tried to arrest him.

'Capsicum spray was used, OC spray, and significant force was used to arrest him,' Inspector Boutouridis said.

'I want to deliver a strong message that this was not a random attack, we have one offender in custody and there are none outstanding.'

Mr Anderson was treated at the scene before being rushed to hospital. He sadly died en route as a result of his injuries.

A crime scene has been set up in the area and residents have been interviewed by police.

Mr Anderson (pictured, left) was unconscious and suffering from severe head wounds when emergency crews arrived

The young man was suffering severe head wounds and was unconscious when emergency crews arrived

Residents along Pavilion Street and Bridge Road heard sounds of moaning coming from a small park

Inspector Boutouridis said the 20-year-old is expected to be charged with murder later today.

He has been taken into custody and is currently being questioned at Manly police station.

'The 26-year-old died at the scene and he is a local and the 20-year-old offender was arrested and taken to Manly Police Station,' Inspector Boutouridis told media.

He is urging witnesses to come forward and inform police of any information they may have.

Mr Anderson was treated at the scene before being rushed to hospital but sadly died en route as a result of his injuries

Mr Anderson's family have attached a note to their bin outside their home asking for their privacy to be respected during this time

'I am confident at this stage this is not a random attack,' he said.

'In fact I am certain the two fellows knew each other, both young men, I don't know the circumstances that lead to them being at the reserve this morning at Queenscliff, that's why I am appealing to the community to assist us.'

Residents told 9News they heard moaning sounds coming from Pavilion reserve about 5.30am.

'We started to hear aggressive moaning and it just kept getting louder and louder,' Kim Luker said.

'Then at 6.10am it was really loud and then all of a sudden it just stopped.'

Detective Inspector Michael Boutouridis said the 20-year-old is expected to be charged with murder later today