An Adelaide school was locked down after a teenage boy called police, telling them he was on the school oval armed with a loaded speargun.

Police said the boy rang triple zero at about 8.30am (CST) on Thursday.

But they said the boy made no known threats to fellow students or staff at Mount Carmel College at suburban Rosewater.

They said the incident might have been sparked by family issues.

The boy was taken into custody after about 45 minutes of negotiations and is undergoing medical treatment.

"Clearly he was standing on the oval with the speargun. The speargun was armed and ready to be activated, although it was pointed at the ground and not pointed at anybody," Chief Inspector David O'Donovan told reporters at the scene.

"He was upset. He was obviously talking to someone on his mobile phone and once we were in a position we commenced to communicate with him.

"Members of his family did attend at our command post and they assisted us with our activities."

Insp O'Donovan said police would not discuss the content of the boy's phone conversation with the emergency communications and whether or not he made any threats to harm himself.

But he said the boy did not display any overt aggression to police at the scene.

"Nevertheless he was on the oval, he was armed and it was a potentially dangerous situation," he said.

people like these make us all look bad...

not cool

That looks like Lethal

people like these make us all look bad...

not cool

hehe, i was thinking of saying the same thing!

Correct me if i'm wrong but wasn't that someone from spearoz forums? After a few Drinks?