Australian authorities have warned the public that a small radioactive capsule has been lost in Western Australia.

The pea-sized capsule is believed to have fallen off the back of a truck between the Gudai-Darri Airstrip and the Perth suburb of Malaga.

Teams of people deployed by the Department of Fire and Emergency Services are currently searching for the missing capsule, which could have fallen off anywhere on the 1400-kilometre journey.

Australian correspondent Oliver Peterson says the circumstances surrounding the lost capsule are still unknown, as the capsules are generally locked in a box on the truck.

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