Teachers charged with child sex abuse

More arrests are expected after police charged two former Sydney schoolteachers with child sex offences.

The allegations go back to the 1980's, when both worked at Patrician Brothers' College in Blacktown.

Last night's arrests came as the Federal Government announced a Royal Commission into child abuse.

Science teacher Brother Martin Harmata is known to thousands of western Sydney school children.

The 59-year-old outdoorsman with 30 years of service at Patrician Brothers' College in Blacktown is highly regarded. But now Brother Harmata stands accused of the sexual abuse of two schoolboys, aged 12 and 13, in the 1980's.

Parents are shocked.

"I does concern me actually, I didn't know about it," one father said.

The other arrested man is 58-year-old Alan James Pollock, a former relief teacher at the college, and at a local primary school.

He's accused of molesting one of the same boys as well as an eight-year-old girl during the late eighties.

Both men were arrested last night as part of a sex crimes investigation that has lasted more than a year.

While detectives said yesterday's arrests are not closely linked, Seven News understands there is other members of the staff who worked at the school over the same period who is currently under investigation.

The Catholic Education Office won't comment but issued a statement saying that they are working closely with the police.

Martin Harmata was only removed by Patrician Brothers in January, after police made the school aware of the allegations.

"I'm sure today will be a day of great fear and agitation about how this is going to affect the Patrician Brothers brand, and the potential for enrolling boys in that school in the future,” former priest Father Kevin Lee said.

Harmata will reappear in court tomorrow, Pollock was bailed until December.

Police have urged any victims of child abuse or child sexual assault to report it, no matter how long ago it occurred.