Syd terror accused teen released on bail

A teenage boy facing terrorism charges in Sydney will live under effective house arrest after he was granted bail.

The 15-year-old Georges Hall schoolboy was allegedly one of five people involved in a terror plot to target government buildings, including federal police headquarters.

Supreme Court Justice Michael Adams said that, on the Crown case, the teenager was aged just 14 when he was overheard on tapped phone calls having "very worrying" conversations with men who were all "significantly older" than he.

In handing down his decision, Justice Adams said the teenager suffered a "psychological reaction which has gravely affected his mental health" and that his condition could worsen in custody.

Members of the boy's family were in court as the decision was handed down, crying and waving to their young relative as he broke into a smile on the court's prison-link screens.

The teenager must comply with bail conditions including a curfew, and a ban on internet use or owning a mobile phone.

His family agreed to put up $750,000 in security and offer a $100,000 cash bond.