Netherlands New Guinea (Dutch: Nederlands-Nieuw-Guinea) refers to the West Papua region while it was an overseas territory of the Kingdom of the Netherlands from 1949 to 1962. Until 1949 it was a part of the Dutch East Indies. It was commonly known as Dutch New Guinea. It contained what are now Indonesia's two easternmost provinces, Papua and West Papua (administered under a unified government prior to 2003 under the name Irian Jaya).
During the Indonesian Revolution, the Dutch launched 'police actions' to capture territory from the Indonesian Republic. However, the harsh methods of the Dutch had drawn international disapproval. With international opinion shifting towards support of the Indonesian Republic, the Dutch managed in 1949 to negotiate for the separation of Netherlands New Guinea from the broader Indonesian settlement, with the fate of the disputed territory to be decided by the close of 1950. However, the Dutch in coming years were able to argue successfully at the UN that the indigenous population of Netherlands New Guinea represented a separate ethnic group from the people of Indonesia and thus should not be absorbed into the Indonesian state.
In contrast, the Indonesian Republic, as successor state to the Netherlands East Indies, claimed Netherlands New Guinea as part of its natural territorial bounds. The dispute over New Guinea was an important factor in the quick decline in bilateral relations between the Netherlands and Indonesia after Indonesian independence. The dispute escalated into low-level conflict in 1962 following Dutch moves in 1961 to establish an autonomous Papuan Government.
Following the Vlakke Hoek incident, Indonesia launched a campaign of infiltrations designed to place pressure on the Dutch. Facing diplomatic pressure from the United States, fading domestic support and continual Indonesian threats to invade the territory, the Netherlands decided to relinquish control of the disputed territory in August 1962, agreeing to the Bunker Proposal on condition that a plebiscite to determine the final fate of the territory be conducted at a later date. The territory was administered by the UN temporarily before being transferred to Indonesia on 1 May 1963. A plebiscite, the Act of Free Choice, was eventually held in 1969 but the fairness of the election is disputed.