CANBERRA (Reuters) - Australia's Labor Party on Sunday elected Bill Shorten to lead it in opposition, help it rebuild support and end bitter divisions after suffering its worst election defeat in a century.
Shorten will be the party's third leader in four months and takes over as new conservative Prime Minister Tony Abbott prepares for the first sitting of parliament since winning a general election on September 7.
Labor was thrown out of office after six years in power after the party dumped the country's first female prime minister, Julia Gillard, and restored a former prime minister, Kevin Rudd, to power just weeks before the election.
Shorten's win follows a month-long vote by the party's 40,000 members, with the results combined with the vote of Labor's lawmakers.
"Today the entire Labor Party chose a leader and chose an alternative prime minister," acting opposition leader Chris Bowen said.
The ballot of the party's wider membership was a first in Australia, but follows a trend to make parties more democratic in Britain, Canada and New Zealand.
Shorten's victory marks a win for the party's right wing faction in his home state of Victoria, where he had built a strong following as a union leader before he entered parliament.
Shorten, 46, came to national prominence as head of the powerful Australian Workers Union.
He was elected to parliament in the 2007 election that ended almost 12 years of conservative rule and resulted in Rudd becoming prime minister for the first time.
Gillard left parliament at the September election, but Rudd is still a member and could take up a senior role in opposition.
Shorten is married to the daughter of Governor-General Quentin Bryce.
(Writing by James Grubel, reporting by Morag MacKinnon; Editing by Robert Birsel )