Australians go to the polls Saturday to choose between Rudd of the Labor Party and Tony Abbott, leader of the conservative Liberal-National coalition,The Australian reported Friday.
Rudd, who was prime minister from 2007 to 2010, returned to the leadership in June after toppling Julia Gillard, the country's first female prime minister.
Rudd said only 3 percentage points separated him from Abbott.
"There are 23 million people who live in Australia. And, of the number of voters, if you're looking at about 3 percent, that's somewhere between 300,000 to 400,000 Australians who we need to get on our side," he said.
Strategists predict the Labor Party could lose about 20 parliamentary seats, dropping its representatives to 50.
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