Counter-terrorism investigators are poring over swathes of seized material as they try to uncover how father-and-son shooters committed an atrocity that killed 15 people and injured many more.
Sajid Akram, 50, and his son Naveed, 24, fired at scores of people at Bondi Beach on Sunday night who were celebrating the Jewish festival of lights.
The premeditated actions were "a barbaric attack against Jewish Australians", Australian Federal Police Commissioner Krissy Barrett said.
"It appears the alleged killers were interested only in a quest for a death tally," she told reporters.
The top cop said early indications pointed to a terrorist attack inspired by Islamic State.
There was no evidence to suggest other people were involved in the attack but she cautioned it was an initial assessment and subject to change.
"Alleged evidence has provided investigators with a swathe of information that has enabled them to make this initial assessment about the alleged individuals involved and their motivations,'' Ms Barrett said.
The NSW joint counter-terrorism team continued to review material seized during search warrants, she said.
Police shot dead Sajid Akram and his son remains in hospital in a critical condition under police guard.
There are 22 injured patients in Sydney hospitals, three in a critical condition and six in a critical but stable condition.
NSW Police Commissioner Mal Lanyon said officers found two home-made Islamic State flags in a car, registered to Naveed, where they also defused two improvised explosive devices.
He confirmed the pair had travelled to the Philippines but noted the reasons for the trip were still being investigated.
"We continue to work through the motive of this tragedy, and we'll continue to do so. It's really important that our investigators continue to be given time to do that," Mr Lanyon said.
"This is a very complex investigation."
Prime Minister Anthony Albanese refused to give further details when pressed on intelligence sharing from Manila.
Mr Lanyon was challenged about why Sajid Akram was granted a permit allowing him to carry six long firearms four years after his son came to the attention of ASIO for affiliating with a radical Islamist preacher in Sydney.
Nearly 260,000 gun licences have been issued across the state, according to latest official figures.
Premier Chris Minns stepped in to defend the police force, saying sufficient resources were devoted to end the shootings.
"(The police officers) engaged the gunmen on a foot bridge with handguns, the offenders had long-range rifles," Mr Minns told reporters.
"There are two police in critical care ... they weren't shot in the back as they were running away - they were shot in the front."
He signalled parliament would be recalled before Christmas to pass tougher gun laws as he urged NSW residents to continue donating more blood to victims.
Mr Albanese said national laws would be strengthened to limit the number of guns per person and citizenship requirements in owning them.
"The very nature of our gun laws means that they are only as strong as the weakest link," he said.
Authorities have ramped up security around Jewish sites, as well as Adelaide Oval before Wednesday's Test cricket match.
Among the 15 Bondi victims were a 10-year-old girl, an 87-year-old Holocaust survivor, a retired police officer and a father who ran at the gunmen, hurling a brick.
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