Emergency service crews were called to the school after a call was received claiming a device was on the premises.

Notices were sent to parents informing them that the school had been evacuated, with the students, teachers and staff all sent to nearby South Dubbo Primary School.

To allay fears the notice also stipulated in bold type that all students were safe.

Roughly two hours later a further notice was sent advising that all staff and students had returned to the grounds of St Laurence's and that classes had resumed as normal.

Meanwhile, Bathurst police have confirmed a bomb threat to The Assumption School earlier on Thursday morning was a hoax.

They were called to the scene after the school received a phone call about an explosive device at 10.40am.

It is not known whether the Dubbo and Bathurst hoaxes are related to other false claims made at schools across Australia in recent weeks.