ASIO examined Bondi Beach gunman Naveed Akram in 2019 for close ties to Islamic State cell

Australia's domestic intelligence agency, ASIO, examined one of the Bondi Beach gunmen six years ago over his close ties to a Sydney-based Islamic State (IS) terrorism cell, the ABC understands.

Naveed Akram, 24, and his father, Sajid Akram, 50, killed 15 people on Sunday evening when they opened fire on the Chanukah by the Sea event celebrating the first day of the Jewish festival.

Naveed Akram is in hospital under police guard after his father was shot dead in an exchange of gunfire with police on Sunday.

Heavily-armed police on Sunday night raided their home in Bonnyrigg, in south-west Sydney, as well as an Airbnb property in Campsie where the men had been staying.

The ABC understands investigators from the Joint Counter Terrorism Team (JCTT), a unit comprised of state and federal agencies, believe the gunmen had pledged allegiance to the IS terrorist group.

Two IS flags were found in their car at Bondi Beach, according to senior officials speaking on condition of anonymity.

One flag could be seen in footage from the scene on the bonnet of the car.

A senior JCTT official, speaking on condition of anonymity, said ASIO took an interest in Naveed Akram six years ago after police foiled plans for an IS terrorist attack.

Prime Minister Anthony Albanese confirmed Naveed Akram first came to ASIO's attention in October 2019 and was under investigation for a period of six months but there was an assessment he posed no ongoing threat.

The official said Naveed Akram was closely connected to Matari, who is serving seven years in jail for planning an IS insurgency as the self-declared Australian commander of the terrorist group.

Matari was part of an IS cell with several other Sydney men who have since been convicted of terrorist offences and were also close to Naveed Akram, according to sources with close knowledge of the matter.

ASIO director-general Mike Burgess said on Sunday that one of the gunmen was known to the agency, but did not specify which man.

"One of these individuals was known to us, but not in an immediate-threat perspective, so we need to look into what happened here," he said.

The JCTT comprises ASIO, NSW Police, the Australian Federal Police and the NSW Crime Commission.