The Prime Minister's decision to announce the election date eight months out has upset some in the Labor caucus but other MPs, from both sides of politics, say it's a masterstroke.

Julia Gillard says she hopes her decision to announce the September 14 election date will force debate on policy.

Treasurer Wayne Swan hopes it draws attention to the Coalition's lack of policy costings.

"They cannot be allowed to get to the election without detailing the costing of their policies," he said.

"From the May budget on there is absolutely no excuse for the Opposition to fail to put forward costed policies."

Privately some Coalition MPs say the announcement was a savvy political move but Opposition frontbencher Barnaby Joyce says it should not be taken seriously.

"It's all so irrelevant, what happens if there's a change of leadership in the Labor Party there will be an election straight away," he said.

But at least one supporter of former prime minister Kevin Rudd believes the move will lock in support for Ms Gillard, "virtually ruling out" any chance of a leadership change.

Ms Gillard made the election announcement during a speech to the National Press Club.

"I do so not to start the nation's longest election campaign - quite the opposite," she told the audience.

"It should be clear to all which are the days of governing and which are the days of campaigning.

"Announcing the election date now enables individuals and business, investors and consumers to plan their year."

Ms Gillard says she will advise Governor-General Quentin Bryce to issue writs on Monday, August 12 to dissolve the House of Representatives.

As part of her agreement with independent MPs Rob Oakeshott and Tony Windsor, Ms Gillard had agreed to hold the election in either September or October.

Opposition Leader Tony Abbott has welcomed the election date announcement and declared the Coalition ready to lead.

Mr Abbott says the Coalition is offering "positive plans for a stronger economy", including scrapping the carbon and mining taxes.

"As I've often said, we are a great country and a great people let down by a poor government," he said.

Opposition frontbencher Arthur Sinodinos says the coalition will make a series of policy announcements in the coming months, with full costings available before the election.

"There'll be a sequence of policy releases over the next few months," he said.

"That's been the consistent strategy of the Opposition with full costings available before the election which will take into account the latest official numbers which the government can provide."

Look back at the reaction to Ms Gillard's announcement earlier this afternoon (all times AEDT):

5:27pm:

The Australian Electoral Commission is encouraging people to ensure they are enrolled to vote, given the election date has now been announced.

People who are 17 but will be 18 on or before September 14, can enrol now.

If you have moved and need to update your details, you can go to www.aec.gov.au.

The AEC says about 1.5 million people are missing from the electoral roll.

The AEC says about 1.5 million people are missing from the electoral roll. ( ABC Local: Jim Trail )

5:20pm:

Labor MP Michael Danby, who is Jewish, says he is aware that the election date coincides with Yom Kippur, the most holy day on the Jewish calendar.

"As a matter of personal conscience I will be unable to participate on election day," he said in an email.

"It is my practice, with my wife Amanda, to observe Yom Kippur (the Jewish Day of Atonement)."

Mr Danby says he's contacted Special Minister of State Gary Gray to help ensure the "fullest participation" of Australia's 120,000 Jews through things like postal voting and pre-polling.

Mr Danby ends his email by noting: "Yom Kippur 2013 is the 40th anniversary of the Yom Kippur War, when a tough female PM, after initial setbacks, won a great victory."

4:57pm:

Independent MP Bob Katter, who has started Katter's Australian Party, says he is glad to have extended notification of when the election is.

"Our party needs time," he told reporters in Bundaberg.

"Every week that goes by we're rolling out an extra five branches. So, the more time we've got, the more happy we are."

Mr Katter says he did not have the slightest hint that Ms Gillard would be announcing the election date, despite assuring reporters that he has "very good ears to the ground in Canberra".

4:51pm:

The Opposition's education spokesman, Christopher Pyne, spoke earlier to ABC News 24 political editor Lyndal Curtis.

He says a September 14 election date is too early to see the final budget outcome for this financial year.

Sorry, this video has expired Pyne says PM failed to mention spending cuts ( Lyndal Curtis )

4:33pm:

One group breathing a sigh of relief with an early election announcement is the Australian Electoral Commission.

AEC spokesman Phil Diak spoke to ABC News 24 earlier this afternoon:

Sorry, this video has expired Electoral Commission backs advance election date notice ( Lyndal Curtis )

4:25pm:

Nationals Leader Warren Truss says the September 14 election will be an opportunity for regional Australia to get its fair share of attention and funding.

He has highlighted a number of issues including the need for better telecommunications "at a price people can afford" and better regional health services.

"For more than five years now, regional Australia has been treated as the ignored poor cousin of the capital cities," he said.

"We know that what is good for regional Australia is good for all of Australia. When the regions are prosperous, so is our nation."

4:18pm:

The ACTU wants the election campaign to focus on job security.

"(Ms Gillard) rightly pointed to global pressures that affects Australia," ACTU president Ged Kearney said in a statement.

"While we can't control the globe, we can influence the policies and laws that protect and serve the Australian people, the most important of which is fairness in the workplace."

The union movement says Mr Abbott now has no excuse for withholding the Coalition's industrial relations policy from the public.

4:15pm:

Here is video of Tony Abbott's press conference:

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4:05pm:

Tony Abbott's opening statement - declaring that the election would be about trust - is a clear reference to former prime minister John Howard's statement when announcing the 2004 election.

Mr Howard said:

Mr Abbott says the Coalition is offering "positive plans for a stronger economy", including scrapping the carbon and mining taxes.

He says the Coalition also has "positive plans" for education, communities, a cleaner environment and border protection.

"As I've often said, we are a great country and a great people let down by a poor government," he said.

Mr Abbott declined to answer media questions, saying he would answer them at the National Press Club tomorrow.

3:59pm:

Bookmakers have been honing their markets following the announcement of the election date.

By the looks of it they already consider the result a forgone conclusion.

Some betting agencies have the Coalition at the Black Caviar odds of around $1.22.

Labor is rated the outsider in the two-horse race at $4.15.

3:52pm:

Opposition Leader Tony Abbott has welcomed the election date announcement and has declared the Coalition ready to lead.

He says voters will face a clear choice when they go to the polls.

"This election will be about trust," he told reporters in Canberra. "Who do you trust to reduce cost-of-living pressures? Who do you trust to boost small businesses and to boost job security? And who do you trust to secure our borders? "That's what this election will be all about."

3:48pm:

Antony Green says Julia Gillard's early election announcement follows the trend towards certainty seen across Westminster governments and robs political pundits of their chance to speculate.

Read his column for The Drum here

3:38pm:

Just to recap on the Prime Minister's speech.

Obviously, she announced the election date, but she also foreshadowed some "substantial" cuts to government spending to pay for significant commitments, including the National Disability Insurance Scheme and an overhaul of school funding.

Ms Gillard says those cuts will be announced in the lead up to the budget and in the budget itself.

3:34pm:

Here is video of the media conference held by Greens leader Christine Milne earlier this afternoon:

Sorry, this video has expired Milne calls for three-year fixed terms

3:29pm:

Since Ms Gillard made the election date announcement just before 1pm (AEDT), the stock market has given up some of the morning's gains.

At 3:25pm, the All Ordinaries index was up 0.2 per cent for the day to 4,918.3.

3:20pm:

The election is 226 days away. That's 5,424 hours. Or 325,440 minutes.

Click here for some more interesting election facts.

3:09pm:

The Australian Chamber of Commerce and Industry (ACCI) says the real advantage of the early announcement is that the final quarter of the year will not be interrupted by the politics of the campaign.

"With the early election announcement, it would be the business community's preference for an early disclosure of the policies, the programs, and the vision of both the Opposition and the Government for Australia's economy to become stronger and more competitive," ACCI's Peter Anderson told reporters in Canberra.

"We want a bidding war between Julia Gillard and Tony Abbott and their parties over who can make the economy more prosperous, more competitive and create more jobs by supporting the private sector."

3:05pm:

Opposition Leader Tony Abbott has called a press conference for 3.40pm (AEDT).

2:55pm:

The federal Member for O'Connor, Tony Crook, says while he is surprised by the Government's early announcement of the election date, he thinks it creates certainty.

"I think in many respects it's a good thing. It gives us some certainty about where we're heading," the WA Nationals MP said.

"People can plan, people can make up their own minds about why it has been done.

"For me, it's business as usual."

2:47pm:

Antony Green has listed every electorate on his blog and what the margins are.

If you're interested, you can check it out here

Sorry, this video has expired Antony Green discusses the call

2:40pm:

Independent MP Andrew Wilkie says he will recontest his Hobart seat of Denison, which he holds by a 1.2 per cent margin on two-party preferred basis.

"My best re-election strategy has always been, and continues to be, to just do my job well."

He says setting an election date early will be good for businesses and investors, but it will be wasted if it leads to a very long election campaign.

"There's still a significant period of this parliament left to run and that demands the Government stay focused on running the country and the Opposition on holding the Government to account."

2:32pm:

Greens leader Christine Milne says the Prime Minister's office gave her a half-hour heads up that Ms Gillard would be announcing the election date in her speech today.

Senator Milne says now's a good time to introduce three-year fixed terms, so that future elections will always be held in the second week of September.

"Wouldn't that be a great thing for the Australian people, so that we didn't have all the game-playing that has gone on in the past," Senator Milne told reporters in Melbourne.

She wants Ms Gillard and Mr Abbott to agree to the change.

2:27pm:

Independent senator Nick Xenophon tells Lyndal Curtis that the PM has "put all of us out of our misery by announcing the election date".

"I think it's good for there to be some advanced notice. It's good for independents and minor parties, I guess, but it also gives some certainty rather than having months of speculation as to when the election will be held. "We now know the date and I think that's probably a good thing in the context of the marathon that now awaits us."

Senator Xenophon's term expires in 2014 and he says that "I'll announce what I'm doing in the next few weeks."

Sorry, this video has expired Xenophon backs advance notice of election date ( Lyndal Curtis )

2:20pm:

Independent Rob Oakeshott plans to announce whether he'll recontest his New South Wales electorate of Lyne in mid-March.

He says it would be a "huge battle" to hold on to his seat.

"I'm certainly at the centre of this 43rd Parliament and decisions made and I stand by all of them," Mr Oakeshott told ABC News 24.

"I fully accept that in some peoples' eyes, I'm hero. In some peoples' eyes, I'm villain. So, it's a very polarised mood that this Parliament has... created, and I accept I'm part of that."

Sorry, this video has expired Oakeshott hails PM's 'shrewd move' ( Lyndal Curtis )

2:13pm:

Independent MP Tony Windsor says he intends to contest the election. The Coalition has preselected independent NSW MP Richard Torbay as its candidate for Mr Windsor's seat of New England. Mr Windsor says he's not sure whether he'll win the contest, but adds that "the mood feels pretty good out there".

Sorry, this video has expired Windsor welcomes election date

2:05pm:

Liberal MP Josh Frydenberg, who is Jewish, has criticised the decision to hold the election on September 14 - which is Yom Kippur, the holiest day of the year for Jewish people.

"In choosing the 14th of September... she disenfranchises many Jewish Australians, it's incredibly sloppy on her part, it's a knee-jerk reaction to pressure that she's coming under within the Labor party," he told ABC News. "It's going to be very difficult for Jewish Australians to participate in election day activities - they spend most of the day in prayer and also they fast."

Ms Gillard says she understands the significance of the day for the Jewish community, but says there are only a limited number of days on which to hold an election because of international commitments and football finals.

She says anyone who cannot vote on that day has the option of casting a pre-poll ballot.

1:57pm:

Greens leader Christine Milne has called a media conference for 2:20pm where she will call for fixed-term elections.

Ms Gillard expects there'll be some debate about the idea, but says it's not a priority for her.

"For me, it's not the upper most policy matter on my mind. I'm very focused on jobs, opportunity, fairness, on getting done the big things that will shape this nation for the future."

1:49pm:

According to the ABC's election analyst Antony Green, the last time a federal election was held in September was in 1946. The most common month for a federal poll is December. Constitutionally speaking, the last date on which this year's election could have been held was November 30.

1:36pm:

The Prime Minister says she announced the election date early so that the nation can focus on "policies, not petty politics".

The move will add pressure on the Coalition to release more of its policies early.

On Sunday, Opposition Leader Tony Abbott launched a "mini-campaign" and released a 50-page policy document.

Shadow treasurer Joe Hockey has said on Twitter: "Election on Sept. 14 is before the final budget outcome is revealed for the current year".

However, under the Charter of Budget Honesty Act, Treasury will release a Pre-election Economic and Fiscal Outlook (PEFO) during the campaign, which provides an update on the budget situation.

1:32pm:

Here's video of the PM making the surprise announcement:

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1:29pm:

Ms Gillard used the speech to the National Press Club to lay the groundwork for an election year battle focused on the economy, arguing that a strong economy is necessary to ensure fairness in education and disability services.

One of the key planks of the Government's 2013 agenda will be overhauling how the education system is funded, in line with the Gonski report.

In today's speech, she's described it as a "moral cause - a crusade".

1:20pm:

Independent MP Tony Windsor says the early announcement of the election date will help provide certainty and stability to the community, but also most importantly to businesses.

"Today's announcement will remove the media speculation of a date and reduce the space devoted to the hype surrounding the choice of a date usually until six weeks before an election. "Putting paid to this practice will encourage the media to present the policy choices allowing Australians to consider their options over a longer period of time."

Ms Gillard says she spoke with Mr Windsor and Mr Oakeshott by phone, to advise them of when the election would be held.

1:15pm:

Antony Green on Twitter:

@AntonyGreenABC : PM copies NZ PM John Key by announcing election day more than half a year in advance ... 9 months notice of the election date. Longer than the 3 months Menzies gave in 1958 and 1961.

1:12pm:

Independent MP Rob Oakeshott says the announcement of the election date will allow the Parliament to run its full term without ongoing speculation.

In a statement, he said: