* Early vote ahead of greater self-rule from Denmark
* Social democrat Siumut ousted from power for first time
* Leftist party doubles parliament seats to 14 out of 31
COPENHAGEN, June 3 (Reuters) - Greenland's main opposition party won a landslide victory in a general election held just before the territory adopts greater independence from Denmark, the island's Home Rule office said on Wednesday.
The leftist Inuit Ataqatigiit (Eskimo Brotherhood) party received 43.7 percent of votes in an early election held on Tuesday, nearly double that share it had in a 2005 vote. The ruling social democrat party, Siumut (Forward), got 26.5 percent.
Talks on forming a new government on the sparsely populated Arctic island, four fifths of which is covered with ice but which is rich in minerals, were expected to begin on Wednesday.
Prime Minister Hans Enoksen had called for the vote, saying Greenland's government should have a fresh mandate ahead of June 21, when expanded home rule becomes effective.
While most politicians in the sparsely populated island want full independence from Denmark, they differ on how fast to proceed.
Mikkel Lund, editor at Greenland's national broadcaster, said Inuit Ataqatigiit favours a slightly less hurried approach towards independence than Siumut. "They want to solve the problems first," Lund said.
Siumut, which has governed the island of fewer than 60,000 people since it won home rule in 1979, saw its share of votes slip from 30.4 percent at the last election. Support for its conservative coalition partner Atassut slumped to 10.9 percent from 19.0 percent.
Movement towards independence for Greenland has been held back by its need for economic subsidies from Denmark, accounting for roughly one third of its gross domestic product.
Denmark has said Greenlanders alone must decide when to cut the final ties after nearly 300 years of Danish rule. Greenlanders voted overwhelmingly last year for increased self-governance. [ID:nLQ341346]
Under the new law Greenland will control its mineral and oil resources and eventually take charge of 32 additional areas of responsibility, including justice and legal affairs, once it becomes economically viable to do so. Greenlandic will become the official language.
Inuit Ataqatigiit, led by Kuupik Kleist, will have 14 seats in the 31-member parliament, up from seven. Siumut will hold nine seats, one fewer than previously, while Atassut will have three seats versus six before.
Greenland's waters potentially hold vast hydrocarbon reserves, although full-scale production is decades away. Denmark and Greenland have agreed to split potential oil income 50-50.
Fishing and tourism currently form the backbone of Greenland's economy. Climate change has caused the ice sheet to melt increasingly fast in recent years, threatening traditional ways of life but making drilling for oil more feasible. (Reporting by Anna Ringstrom; Editing by Richard Balmforth)