Officers executed search warrants at two homes in the regional town of Moree on Thursday, arresting two boys, aged 15 and 16.
It follows the arrest of another 15-year-old boy from the same area in March, who was charged with similar offences.
During the latest round of searches, police seized a number of handwritten notes and pieces of literature alleged to contain extremist references.
The 15-year-old was charged with using a carriage service to transmit violent extremist material and knowingly collecting or making a document connected with terrorism.
The 16-year-old faces one charge of using a carriage service to possess violent extremist material.
The latest arrests stem from reports police received in December 2025 that a teenager was accessing extremist material online.
Police searched a home in Moree on March 27, arresting the 15-year-old and allegedly seizing a mobile phone, a ballistic-style vest and several notebooks.
Forensic examination of those items prompted the latest searches, police said.
The 15-year old who was arrested in March has been charged with using a carriage service to possess violent extremist material and possessing or using a prohibited weapon without a permit.
The two latest boys to be charged are due to appear before a children's court on Friday.Â
Police urged anyone with information about extremist activity or possible threats to the community to come forward.
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