Australia's prime minister-elect Kevin Rudd has outlined his priorities after winning a sweeping general election victory over outgoing PM John Howard.
Mr Rudd signalled a swift break with his predecessor's policies by promising to sign the Kyoto Protocol and pull troops out of Iraq.
He also promised to attend next month's UN climate change summit in Bali.
Meanwhile, Peter Costello - Mr Howard's nominated successor - has turned down the post of opposition leader.
The BBC's Phil Mercer in Sydney says that Australia's conservatives are wounded and fractured and it could take them years to recover from this election defeat.
With just over 75% of ballots counted, Mr Rudd's Labor has 53% of the vote and Mr Howard's conservative coalition 46.5%.
US President George W Bush - a close ally of Mr Howard - was among the world leaders to congratulate Mr Rudd on his election victory.
In a statement Mr Bush said he looked "forward to working with this new government to continue our historic relationship".
More than 13.5m of Australia's roughly 21m people registered to vote
Electors choose candidates for all 150 seats in the lower House of Representatives and 40 of the 76 seats in the upper house, the Senate
PM John Howard (above) has led the conservative Liberal-National party coalition to four election wins since 1996
Kevin Rudd is taking the centre-left Labor Party to the polls for the first time as leader
Election issues: The economy, environment and war in Iraq
Mr Rudd, a former diplomat, is of the same mind, says the BBC's Phil Mercer in Sydney, but his plans for a phased withdrawal of 500 Australian combat troops from Iraq may put those close ties to the test.
The Labor leader does however support the military campaign in Afghanistan and plans to visit the United States early next year.
UK Prime Minister Gordon Brown also congratulated Mr Rudd and welcomed the incoming prime minister's pledge to sign up to the Kyoto Protocol on capping greenhouse gas emissions.
In his first news conference since his election, Mr Rudd promised "action and action now" on climate change.
He said he looked forward to meeting Indonesian President Susilo Bambang Yudhoyono after receiving his invitation to the Bali conference.
Mr Rudd promised to name his new cabinet by the end of the week, with one of his key appointments expected to be Julia Gillard as deputy prime minister.
If appointed, Ms Gillard will become the first woman to hold the position.
In his victory speech on Saturday, the Labor leader said: "Today the Australian people have decided that we as a nation will move forward.
"To plan for the future, to prepare for the future, to embrace the future and together as Australians to unite and write a new page in our nation's history."
The swing to Labor is so far more than 6% and analysts say the party is on course for a clear majority in the 150-seat parliament for the first time since it lost to Mr Howard in 1996.
Our correspondent says this is a humiliating defeat for Mr Howard and a day Labor has waited many years to see.
Its supporters are hoping Australia will become more compassionate under Kevin Rudd, he says.
The party's environment spokesman, Peter Garrett, told the BBC Australia was on the brink of fundamental change.
"Australians have decided that they are going to throw out a government that has been delinquent on climate change, that has tried to recast our industrial relations laws, and which hasn't shown any capacity to measure up to the challenges of the 21st Century."
In his concession speech, Mr Howard said: "This is a great democracy and I want to wish Mr Rudd well.
"We bequeath to him a nation that is stronger and prouder and more prosperous than it was eleven and a half years ago."
There were few moments of cheer for the Liberals.
Former political journalist, Maxine McKew, is close to removing Mr Howard from Bennelong and make him the first sitting prime minister to lose his seat for 78 years.
Voters in Bennelong have elected Mr Howard in 13 consecutive elections over 33 years.
Mr Rudd is expected to be sworn in as prime minister next week.