Posties, long the target of canines, are now worried about losing their fingers to technological advances.
They say the top of a delivery worker's index finger was severed recently by the sharp edge of a spring-tensioned letterbox flap at Keswick in Adelaide.
The worker's finger got trapped by the spring-tensioned flap and was pushed hard against a sharp brass edge, severing the top.
Australia Post says spring-tensioned letterbox flaps are common in newer models.
Communications manager Joshua Zugajev is urging householders to help posties survive their daily runs.
"Removing or disabling the spring in your letterbox is very straightforward and can be done with a pair of pliers," he said.
"You can simply bend the spring back so it doesn't put pressure on the flap, or completely remove it."
Posties will make a special delivery in coming days, writing to householders with spring-tensioned letterbox flaps to tell them of the potential danger and asking them to remove the spring.
