UPDATE: 7.40pm: 

St John the Baptist Catholic Primary School is cooperating with police as they investigate this morning's bomb threat, according to principal Tim Franzmann.

In a letter addressed to the parents of children in outside school hours care, which was operating at the time, Mr Franzmann said any security threats were taken seriously.

"The school and outside school hours care immediately initiated its relevant emergency procedures," he said.

"As per our procedures, children, staff and visitors from St John the Baptist Catholic Primary School and the outside school hours care program were evacuated and police conducted a full search of the site."

Mr Franzmann said parents were notified of the evacuation via SMS, while children were able to discuss the incident with staff.

"Police declared the site safe and advised the service was able to resume.

"To ensure children were settled, they were offered a debriefing session and an opportunity to discuss with me the events of the morning.

"The outside school hours care program conducts drills for emergency scenarios every three months as per legislation and the practising of these drills assisted in ensuring the safety of children, staff and visitors.

"In this case, all children, staff and visitors reacted appropriately to the situation, and this ensured the children remained settled and calm."

EARLIER: 

POLICE have launched an investigation into a bomb threat at a Clinton school today.

Teachers were forced to evacuate St John the Baptist Catholic Primary School this morning after the threat was made. 

But there were no students, as it is a pupil free day.

Police arrived at the school at about 8.50am after they were notified by firefighters.

Police alerted staff before arriving at the school and staff evacuated quickly.

It's not yet known if police have any information on who was behind the threat. 

Staff were allowed to returned to work at about 9.20am after a police sweep of the school turned up no explosives.

More to come