A young man is being spoken to by police after he allegedly put a pipe bomb into a rural Coromandel letterbox last night.
The 18-year-old was "playing around with fireworks" when he made the explosive, Inspector Steve Kose of northern police communications said.
The bomb was discovered by the owner of the Waihi property after he spotted a vehicle pull up to the letterbox about 10pm and took note of the vehicle's registration number.
"Then he opened the letterbox and he saw a 15cm pipe in there," Mr Kose said.
The owner was lucky the bomb did not explode, he said.