Which Oceanian territory's flag is a green-white-green vertical triband?

Norfolk Island’s flag is the Oceanian territory flag designed as a green-white-green vertical triband.

The flag was adopted in 1979, when Norfolk Island received limited self-government. Its three vertical bands have proportions of 7:9:7, making the central white stripe slightly wider than either green stripe. A green Norfolk Island pine stands in the middle of the white band.

The pine is more than a decorative emblem: Araucaria heterophylla is native to Norfolk Island and is the territory’s official tree. The green bands symbolize the island’s vegetation and fertile land. The design is therefore both a simple triband and a visual portrait of the island’s distinctive landscape.

The flag is sometimes confused with Nigeria’s flag because both use green-and-white vertical bands. Nigeria’s flag has no central tree, however, while Norfolk Island’s includes the prominent pine. The flag’s legislation was enacted through the Norfolk Island Flag and Public Seal Act 1979, which also specifies the 1:2 aspect ratio.