Three men facing charges over the murder of police employee Curtis Cheng at Parramatta, in Sydney’s west, have also been charged with being members of a terrorist organisation.
Mr Cheng was shot dead by 15-year-old Farhad Jabar outside NSW police headquarters in October.
Jabar was killed when police officers returned fire.
It was later revealed the teenager had been radicalised and his attack had been linked to terrorism.
On Wednesday, the NSW Joint Counter-Terrorism Team charged Talal Alameddine, 23, Mustafa Dirani, 22, and Raban Alou, 18, with being members of a terrorist organisation.
The Australian Federal Police and NSW Police have declined to name the organisation.
The men are currently in custody at a Goulburn jail having been previously charged with offences relating to Mr Cheng’s murder.
Dirani is also charged with knowingly participating in the supply of a pistol and knowingly participating in a criminal group.
He is due to appear in Parramatta Local Court on Thursday.
Alameddine is also charged with knowingly participating in a criminal group, supplying a pistol to an unauthorised person, acquiring a pistol contrary to a Firearm Prohibition Order and hindering the discovery of evidence.
Police said Alou had previously been charged with aiding, abetting, counselling and procuring the commission of a terrorist act.
Alou and Alameddine are due to appear in court next month.
All have been bail refused.