Fiji customs and police who have found a New Zealand-based yacht after a search near Savusavu have taken the captain and two crewmembers into custody.
Customs said a search of the boat led to the seizure of a large quantity of a mix of ammunition.
Revenue and Custom chief executive Visvanath Das said the agency's intelligence and profiling processes were determining high-risk vessels and collaborative efforts with Fiji police and the navy led to the seizure.
He said customs last weekend discovered a massive drug find on an Australian-based yacht and now officers had exposed another smuggling attempt.
Police commissioner Sitiveni Qiliho said Fiji continued to quash the notion that a small Pacific Island nation cannot effectively police its borders.