Four teenagers aged 14 to 17 plotted to buy guns and attack Jewish people days after a bishop was stabbed in a Sydney church, local police are understood to have said.

The allegations come after five teens were last week charged with a range of offences, including conspiring to engage in or planning a terrorist act.

According to News Corp Australia, Sydney Police alleged the group of five “adhered to a religiously motivated, violent extremist ideology.”

In court documents cited in the reports, police claim the group is part of a network which includes a 16-year-old who has been charged with a terrorist act after stabbing Bishop Mar Mari Emmanuel.

The bishop was attacked during a service at the Assyrian Christ the Good Shepherd Church on 15 April.

Following the attack the teens used the encrypted messaging app Signal to plan an attack on Jews, News Corp Australia publications reported.

"I wanna die and I wanna kill... I'm just excited... Is your plan to get caught or die or escape?" a 17-year-old allegedly said in a group chat on 20 April.

A 16-year-old allegedly responded: "We're gonna be planning for a while... we prefer to escape, but whatever happens, it's the qadr (predetermination) of Allah."

In a separate message exchange, a 15-year-old allegedly said: "I really want to target the yahood."

One of the teenagers reportedly said: "I know the bloke who done it," in reference to the church attacker.

According to News Corp, who cited a police fact sheet submitted to the Sydney Children’s Court, two of the defendants charged last week discussed buying guns on 19 April, the same day the bishop's alleged attacker was charged.

New South Wales Police Force told the Associated Press it could not confirm the accuracy of the reports or provide a copy of the police fact sheet submitted to the court.

According to the Independent, lawyer Ahmed Dib, who represents two of the boys charged last week, said he had not read the newspaper report and could not comment on its accuracy.