Gillard wins caucus vote 71-31

It's been an emphatic victory for Julia Gillard in the leadership ballot held by Labor this morning, with the prime minister defeating Kevin Rudd in the caucus vote 71 votes to 31.

Returning officer Chris Hayes announced the result alongside his deputy Dick Adams at about 11:20 am this morning. Labor parliamentary members were in the caucus room for more than an hour.

Hayes said the atmosphere in the party room was "tense" and that Gillard had urged the party to unite. He also said Rudd had promised to help bring the party together.

Initial reports from journalists had the numbers at 73-29, before the official confirmation verified the margin at 40 votes in favour of the prime minister.

Both Julia Gillard and Kevin Rudd emerged from the caucus room soon after the announcement surrounded by their key backers. They are expected to address the media later today.

As pundits have already noted, Rudd's return of less than a third of votes leaves him with little base support should he want to take another tilt at the leadership.

Gillard's supporters will hope the strong vote of confidence from her colleagues will lay the foundations for a strong run in to the next federal election.