Police are hunting for thousands of detonators stolen from the Philippi warehouse of arms maker Denel, in a case described as "extremely sensitive".

National police spokesman Vishnu Naidoo confirmed today that the theft of the weapons components from the Denel Munitions warehouse had been discovered on Friday.

A case of housebreaking and theft is being investigated by detectives of the Western Cape's organised crime unit.

It is the second theft of munitions at the premises in two months. In the earlier case, ammunition was stolen, allegedly by an employee, and that case is being heard in court.

Naidoo refused to divulge further details about what munitions, ammunition or explosives had been stolen from the plant on Friday. This was "due to the sensitivity of the investigation".

"It's a national key point, so certain requirements must be ad-hered to in terms of the National Key Points Act," Naidoo said.

But Denel Munitions chief executive Monwabisi Kalawe, formerly the head of Cape Town In-ternational Airport, said today that more than 3 000 detonators were missing from the warehouse.

Typically these were used to initiate an explosive chain and were found in most products manufactured by the company, he said.

"On their own they are harmless," Kalawe said.

"I can assure you that the police are investigating, including the police's National Key Points Unit."

With acknowledgements to Murray Williams and Cape Argus.