Seven teenagers have been arrested by Australian police for allegedly belonging to a network that follows "violent extremist ideology".

It follows an attack on an Assyrian bishop while he was livestreaming a sermon in Sydney last week. Bishop Mar Mari Emmanuel was injured in the attack at The Good Shepherd Church along with three others.

He publicly forgave his attacker and called for peace after riots broke out in the aftermath of the attack. 

A 16-year-old boy was arrested over the stabbing and is said to be part of the same network, police said. He was charged with committing a terrorist act last Friday and faces life in prison. 

The seven arrested during raids across Sydney on Wednesday are aged 15 to 17. 

New South Wales Police Deputy Commissioner David Hudson said the suspects were considered an immediate threat, although Australian Federal Police Deputy Commissioner Krissy Barrett said there was no evidence of specific targets or timing of an intended "violent act", AP news agency reports.

"We will allege that these individuals adhered to a religiously motivated, violent extremist ideology," Hudson told reporters.

"It was considered that the group ... posed an unacceptable risk and threat to the people of New South Wales, and our current purely investigative strategies could not adequately ensure public safety."

X, formerly Twitter, is contesting a court order to remove clips of the livestream showing the bishop being attacked.