INTERACTIVE: Gillard's long shot on poll

Australians will go to the polls on September 14 after Julia Gillard revealed the election date 7½ months out in a bid to reboot her political prospects and wrongfoot the Opposition.

The bold play caught Tony Abbott off-guard and was not known to many in cabinet, although Ms Gillard had told key ministers and the Greens and independents whose support allowed her to form government in 2010.

The move carries big risks for the Prime Minister, including the prospect of near-constant electioneering through autumn and winter right into the AFL and NRL finals.

Ms Gillard said her aim was to end the uncertainty of election speculation and allow her to concentrate on governing until the official campaign begins.

''I today announce that later this year, I will advise the Governor-General to dissolve the House of Representatives with writs to be issued on Monday the 12th of August for an election for the House and half of the Senate, to be held on Saturday the 14th of September,'' she told the National Press Club.

The break with tradition gained the approval of the independents and brought a call from the Greens to make the arrangement permanent by introducing fixed terms as apply in most states.

The key independent MP Tony Windsor said Australians would otherwise have endured "mini-campaigns and speculation up until the Prime Minister of the day saw a political opportunity to call the election''.

However it drew immediate criticism from the opposition as ''a triumph of tactics over strategy''.

Mr Abbott, flanked by his campaign manager Brian Loughnane, told reporters he was ready - but he refused to take questions.

He explained he would have more to say at his own National Press Club appearance on Thursday.

Channelling his mentor, John Howard, from his 2004 speech, he declared the key focus for Australian voters would be trust.

''This election will be about trust: Who do you trust to reduce cost of living pressures?'' he said.

''Who do you trust to boost small business and to boost job security and who do you trust to secure our borders?

''That's what this election will be all about.''

Privately, Coalition strategists said they were delighted, arguing Ms Gillard had miscalculated and condemned the country to a deeply unpopular extended election campaign.

But the Prime Minister said her decision would actually free her up to govern.

''I do so not to start the nation's longest election campaign, quite the opposite,'' she said. ''It should be clear to all which are the days of governing and which are the days of campaigning.''

Turning more than a century of orthodoxy on its head, she said that beginning the year with the poll date already set would ''enable individuals and businesses, investors and consumers to plan their year''.

''It gives shape and order to the year and it enables it to be one not of fevered campaigning but of cool and reasoned deliberation,'' she said.

She believed the fixed date also removed any excuses Mr Abbott might have for not releasing fully costed Coalition election policies until just before the election.

''They have two things the opposition never had before to enable them to do that: One, they've got the benefit of the fixed election date with several months' notice.

''Two … they've got more resources available to them than an opposition has had before in the history of our nation to produce proper costings.''

Mr Abbott's strategists said they would not be pressured into changing campaign or policy timetables by the government.