Australia is a constitutional monarchy and a federal commonwealth in Oceania comprising the Australian continent and the islands of Papua New Guinea, Tasmania and New Zealand. Since the federation of the seven original British colonies in Australasia in 1901, it has maintained a peaceful liberal democratic system of government. Its current Prime Minister is Kevin Rudd of the Labor Party, in coalition with the Australian Greens. The Australian continent was first settled some 60,000 years ago. The first human settlers arrived in New Zealand from Polynesia around 1200AD.