Papua, the southern section of the country, was annexed by Queensland in 1883 and the following year became a British protectorate called British New Guinea. It passed to Australia in 1905 as the Territory of Papua. The northern section of the country formed part of German New Guinea from 1884 to 1914 and was called Kaiser-Wilhelmsland. Occupied by Australian forces during World War I, it was mandated to Australia by the League of Nations in 1920 and became known as the Territory of New Guinea. Australian rule was reconfirmed by the United Nations in 1947.
In 1949 the territories of Papua and New Guinea were merged administratively, but they remained constitutionally distinct. They were combined in 1973 as the self-governing country of Papua New Guinea (PNG). Full independence was gained in 1975. In the late 1980s a violent secessionist movement broke out on Bougainville. A cease-fire, monitored by Australian troops, went into effect in 1998, and a peace accord that granted the island broad autonomy was signed three years later.
Proposed cuts in defense forces as result of economic reforms demanded by Australia and international organizations sparked a weeklong mutiny in 2001; the government rescinded the cuts and promised to review the mutineers' concerns over foreign economic influences. Sir Michael Somare, of the National Alliance party, became prime minister in 2002. In 2004, Australian police officers were deployed in PNG as part of an aid package designed to help end gang violence and restore law and order in the country, but after the supreme court ruled the following year that the officers' immunity from prosecution and other aspects of the deployment were unconstitutional Australia withdrew the contingent.
In late 2006 PNG's government and its relations with Australia were roiled by the Moti affair. Julian Moti, an Australian lawyer of Fijian descent had been appointed attorney general in the Solomon Islands, was wanted in Australia on child sex charges, and Australia sought Moti's extradition from PNG, where Moti was arrested (Sept., 2006) while in transit. Moti managed to flee with apparent help from PNG officials. An investigation into the incident implicated the prime minister in Moti's flight from PNG, a charge Somare denied; Somare subsequently disbanded the board of inquiry, which issued its report to Somare in Mar., 2007. Elections in June–July, 2007, returned Somare to office, leading a reorganized coalition. The defense minister rejected the board of inquiry report in Oct., 2007, on the grounds that the board had not been legally constituted.
Somare's government subsequently suffered from a number of scandals, including some involving the prime minister's finances. Although he survived a number of no-confidence votes, in Dec., 2010, he faced an investigation by a leadership tribunal over financial allegations. Somare stepped aside as prime minister, and his deputy, Sam Abal, became acting prime minister (and again in April); Somare returned to office in Jan., 2011.
In March, Somare was found guilty of failing to file his financial information properly and was suspended from office for two weeks in April; in June, his son announced his retirement for health reasons (following an April heart operation), but constitutionally it was not an official resignation. In August, an alliance of opposition members and disgruntled government coalition members voted in Peter O'Neill, the works and transport minister and former finance minister, as prime minister; the supreme court ruled that the move was unconstitutional in Dec., 2011. The ruling created a constitutional crisis and a contest for power, with O'Neill's government backed by parliament and generally maintaining control while Somare's continued to be backed by the supreme court. Elections in June, 2012, resulted in a plurality for O'Neill's People's National Congress, and he became prime minister in August with the support of Somare.