How a strategic Pacific island became a complex administrative puzzle for the Australian government.

History · Published 3 October 2026 · Updated 25 October 2026 Swipe more like this →

In short: New Guinea is the world's second-largest island, yet its modern political map is a legacy of colonial mandates and wartime occupation. Once divided between German and British interests, the island's eastern half evolved through Australian administration into the independent nation of Papua New Guinea, a process spanning over sixty years.

The political geography of New Guinea was fundamentally reshaped in the early 20th century. Following the outbreak of World War I, Australian forces seized the northeastern quarter of the island from the German Empire in 1914. By 1920, the League of Nations granted Australia a mandate to govern this territory, viewing it as a strategic necessity that functioned like a fortress for the Australian mainland. This mandate, which lasted until the Japanese invasion in 1941, saw the expropriation and expulsion of German settlers and the transfer of their plantations to Australian owners, many of whom lacked tropical farming experience.

The post-war era brought further administrative shifts. After the Pacific War ended in 1945, the Australian government combined the Territory of New Guinea with the Territory of Papua, which had been under Australian control since 1906. This union, formalized through the Papua New Guinea Provisional Administration Act, created a single administrative entity. Despite this merger, the Territory of New Guinea maintained a distinct legal status until the region finally gained independence as the sovereign state of Papua New Guinea in 1975.

Today, the island remains divided between this independent nation and the Indonesian provinces of Papua and West Papua. The landscape itself is as rugged as its history, featuring a central mountain chain with peaks exceeding 13,000 feet and some of the world's wettest environments. While the island is home to immense linguistic diversity—with speakers of some 700 different languages—the central highlands remain the most densely populated region. Modern economic life relies heavily on mineral wealth, including significant copper and gold deposits at Ok Tedi and Tembagapura, alongside subsistence agriculture that has sustained the island's inhabitants for thousands of years.

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