Australians will go to the polls on August 21, Prime Minister Julia Gillard announced on Saturday.

Gillard on Saturday has left Yarralumla of Australia after asking Governor-General Quentin Bryce to dissolve parliament for an election on August 21.

"This election, I believe, presents Australians with a very clear choice," Gillard told reporters in Canberra on Saturday. " This election is about the choice as to whether we move Australia forward or go back."

Economic strength, education and climate change are to be the Labor Party's top three priorities for a re-elected government.

"Keeping the economy strong so that people can get the benefits of work," Gillard said.

"Keeping investing in education, reforming education, so we can truly offer every child ... the opportunity for a great quality education.

"And thirdly ... I would be saying to Australians we don't have to be afraid of the future - we can master big challenges like climate change."

The Labor Party said would protect the budget's return to surplus in 2013 during the campaign by not going on an "election spendathon".

"The uncertainty is not behind us yet, and economic challenges are still very much with us and hard working Australian families who are doing it tough can attest to that," she said.

The prime minister also stressed a need on stronger protection for the nation's borders.

"And a strong plan, a real plan that takes away from people smugglers the product that they sell."

Gillard noted that Labor had increased expenditure on hospitals by 50 percent in its first term.

Moving forward on health meant training 3,000 nurses and 1,300 General Practices (GPs) during the next three years "all the while as we expand our GP super clinics and implement our health reforms ".

Labor will reveal its climate change policy during the election campaign.

"They will be policies coming from a person who believes climate change is real, who believes it's caused by human activity and who has never equivocated in that belief," Gillard said.

Australians will have until 8 p.m. (AEST) on Monday to register to vote with Gillard confirming writs for the election will be issued at 6 p.m. on the same day.

Gillard would not speculate on how many seats Labor stand to win or lose on August 21, except to say the campaign would be close, tough and hard-fought.

The Opposition Leader Tony Abbott is also expected to hold a media conference in Brisbane, the state capital of Queensland at noon.

The opposition party needs to win an extra 17 seats to get back into government. Labor party headed by former prime minister Kevin Rudd ousted John Howard's government in November 2007.