Australian National Election day is here and votes have been cast but when will we know who is the prime minister of Australia? We explain.

Polling stations opened across Australia at 8am local time in a federal election that may deliver the nation’s sixth prime minister in as many years.

Polling on Australia’s west coast began two hours after the east coast stations opened. East coast stations will close at 6pm, two hours before voting ends in the west.

HOW LONG WILL IT TAKE TO COUNT VOTES?

Counting begins at 6pm, immediately after polling booths close.

Step one is a count of the first preferences in the House of Representatives ballots. Then the the field is narrowed to the two candidates likely to get the most preferences — a two-candidate preferred vote.

Step three is a count of the Senate first preferences.

Preferences will be counted during the week. There is no count Sunday but it is not a day off for AEC staff. There is a lot of work needed to ensure all ballots are accounted for and safe.

Counting begins at 6pm, immediately after polling booths close.. Picture: Saeed Khan/AFPSource:AFP

WHEN WILL WE KNOW WHO HAS WON THE FEDERAL ELECTION?

The first results start appearing about 6.10pm AEST.

More than 4.7 million votes were cast ahead of election day. The huge numbers of pre-poll votes will mean we won’t know the result in some booths for days.

One party usually concedes defeat, often with a phone call, before the winning leader claims victory.

COULD THE RESULTS BE DELAYED?

It could be June 1 or later before we have an official election result.

The Australian Electoral Commission has to wait 13 days after polling day before making the declaration. This is to ensure all postal votes mailed before May 18 have been received. Even then, problems with the count could cause further delay. And the raw numbers show the magnitude of the job.

Some 16.4 million people are enrolled to vote, and close to a third of them cast ballots before today.