A Papua New Guinea man has been arrested at Mount Hagen airport after police found a rocket launcher and grenades packed in the man's luggage.
Police say the man, in his early thirties, had flown from Gulf province.
The Western Highlands Commander, Superintendent Thomas Elu, says the weapon was discovered during a check of the man's belongings.
He says he told police he didn't know anything about the rocket launcher and the nine grenades stowed in his bag.
"When he was apprehended he said he never knew of the items in his bag but their were some people at Kikori in the Gulf province. They had already packed the luggage's in his bag and told him there'll be some people waiting for him at Mount Hagen airport to pick up the items."
Commander Thomas Elu says the man told police he didn't know who was meant to pick up the devices.
He says an expert is still to look at the explosive devices before chargers can be laid.