A poll published on Sunday pointed to a close result in next Saturday's election with the chance of a narrow opposition victory as Australia entered the final week of its tightest election race in many years.
The Aug. 21 vote will decide the fate of the government's 30 percent mining tax on big iron ore and coal projects, and the future of government plans for a $33 billion national broadband network. The opposition has promised to abandon both.
Polls have shown the lead changing hands frequently. A Nielsen poll issued on Saturday showed Prime Minister Julia Gillard's Labor party regaining the lead.
But a poll taken in marginal seats by Galaxy and published on Sunday suggested the opposite.
Gillard said on Saturday that she expected a "photo finish" and in an interview on Sunday she remained upbeat, accusing the opposition of a A$30 billion hole in its policy costings.
"I am feeling fine. I am feeling full of enthusiasm for the final week of the campaign," she told Channel Nine.
The Galaxy poll of 4,000 voters, published in Sydney's Sunday Telegraph, was conducted in 20 marginal seats. It put the opposition coalition ahead overall by 51.4 percent to Labor's 48.6 percent on a 'two-party' basis, eliminating minor parties under Australia's system of transferable voting.
It also showed the conservative opposition might win the 17 seats it needs to take power, or the 14 that would give it a chance of forming a minority government.
On Wednesday, the latest Reuters Poll Trend showed Labor marginally ahead with 50.1 percent support, against 49.9 percent for the opposition, as the tightest race since 1998 pointed to the possibility no single party will form a government after next Saturday's election.
Opposition leader Tony Abbott has declared himself the underdog but has fought a disciplined campaign.
Labor is struggling to hang on to marginal seats in several areas, particularly Queensland, a key resource state where plans to increase taxes on mining and Kevin Rudd's ousting as party leader and prime minister have damaged the ruling party.
Gillard paid tribute to Rudd, who she ousted in a party coup in June, describing him as "brave" for returning to the campaign trail last week after a gall bladder operation to support her.
"I am very grateful for it," she said.