Sydney teen due in court over terror plot

A teenager who was allegedly planning to carry out an imminent terrorist attack in Sydney is due to face court.

It's alleged the 18-year-old was trying to get hold of a gun and was scouting for targets in the city that involved buildings representing authority.

The teen, whose alleged bid to join extremists in Syria was thwarted earlier this year, was arrested in Macquarie Park in Sydney's northwest on Tuesday morning.

Named in media outlets as Tamim Khaja, he is believed to be a former student at Epping Boys High School and was allegedly investigated by counter-terrorism police for preaching radical Islam at the school last year.

The teen has been under surveillance since he allegedly tried to board an international flight from Sydney Airport in February to join the Islamic State terrorist group in Syria.

He was stopped because his passport was cancelled.

He is expected to face Parramatta Local Court on Wednesday charged with one count of planning a terrorism attack and one of preparing for foreign incursions.