A once-trusted teacher is beginning a jail sentence as a registered child sex offender after pleading guilty to charges involving five of his students.

The Corrections boss has been ordered to obey the law or face contempt of court proceedings if he fails to make sure prisoners aren't let out of their cells for an hour every day.

The gunman who killed two Brown University students in the United States remains at large, and there is no indication that authorities have grown closer to identifying the suspect four days after the attack.

Hate preachers who promote violence will face tough new penalties and people spouting racial hatred could have their visas cancelled, in the wake of the Bondi massacre.

A leading epidemiologist says a plan to ditch an online tool tracking respiratory illness is short-sighted, and will leave a big gap in surveillance.

The police union's president says officers now face a long process to regain the public's trust.