The first full day of the Australian federal election campaign began with both sides of politics promising nothing short of a spectacle over the next five weeks, local media reported on July 18.

Prime Minister Julia Gillard on Saturday announced the election for August 21.

According to Australian Associated Press, Gillard kicked off Labor's full-blown campaign on Sunday in Brisbane, while federal opposition leader Tony Abbott will do the same for the Coalition in Sydney.

Gillard has kicked off her first full day of election campaigning in a traditional way, by cuddling countless babies in a Brisbane park.

Gillard and her deputy Wayne Swan attended an event welcoming the babies in suburban Chermside, Brisbane of Australia on Sunday morning.

Gillard told the crowd that it was not the day for big political speeches even though the election was "in train".

"But I would say to the mums and dads who are here, that what I want to see for their children's future is a country where every child ... is going to have a great quality of education."

Gillard also plugged her vision for a sustainable Australia, ahead of a speech on the issue on Sunday.

"Sustainability, not a big Australia, but Australia in which we can protect the lifestyle we've grown up to love," Gillard said.

Opposition leader Tony Abbott, however on Sunday questioned Gillard's commitment to population policy, accusing her of an election fix on the issue.

"It does look like a panicked change in policy with an election in the offing and she hasn't changed anything in practice," Abbott told Sky News.

"I'm not against a higher population and in fact my paid parental leave policy is designed to have more mums having kids and more mums in the workforce feeling they are able to have a larger family."

"But it's got to be sustainable."

The Australian Greens will not nominate a specific population target despite the party's concerns about the issue.

"I'm very interested to really know what (Sustainable Population Minister) Tony Burke and Julia Gillard mean by sustainable," leader Bob Brown told reporters in Canberra.

Limits on population should be dictated by infrastructure such as public transport and housing, the ability of the country to ensure lifestyle into the future and a compassionate outlook on the immigration stream coming to Australia.

"We should use the money from the mining boom to skill and re- skill our workforce rather than having hundreds of thousands of people brought from overseas where they may be needed," Senator Brown said.

Meanwhile, Abbott has moved to neutralize Labor's claims he will reintroduce Work Choices, but has refused to guarantee no worker will be worse off under a coalition government.

The opposition leader has said that if he won office there would be no changes to Labor's industrial relations laws for the first three years of a coalition government.

Prime Minister Julia Gillard has dismissed the pledge, saying Abbott could not be trusted on industrial relations because he had always "thought Work Choices was right".

Abbott said Labor was simply scaremongering on the issue.

A Galaxy opinion poll, published in News Ltd newspapers on Sunday, showed Labor maintaining a two-party preferred lead, 52-48 percent, over the Abbott-led coalition.