The first full day of the Australian federal election campaign began on Sunday 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.

Top bookies have unanimously picked Labor to win, with Centrebet, the online betting company, predicting the coalition to take back up to 14 marginal seats, which is not enough to win government.

Abbott has led opposition for only seven months, while Gillard just three weeks ago helped oust her predecessor Kevin Rudd.

Both leaders took the opportunity on Saturday to warn voters that electing the competition will send Australia backwards on issues such as the economy, climate change, border control and workplace relations.