Labour leader Helen Clark has announced the election will be held on 8 November.
Miss Clark made the announcement at a news conference at 12.35pm on Friday.
She said she had identified the election date some time ago, and is very optimistic of a successful outcome for Labour, which is hoping to be elected for a fourth term.
Miss Clark said trust will be a central theme of Labour's campaign, and the party will be releasing new policy shortly.
She said her Labour-led government had brought about a remarkable transformation for the better in the country's economy and society.
Miss Clark told the media conference the National Party had attacked every major Labour policy aimed at making life better for families. She said National has flip-flopped on issues and only said what it thinks the country wants to hear.
NZ First acted honourably - Clark
Miss Clark told Checkpoint on Friday she would not rule out working with New Zealand First after the election. The party's leader, Winston Peters, is embroiled in controversy over donations to his party and his legal fund.
She said New Zealand First had acted honourably as a party with a confidence and supply agreement, as has United Future.
The Labour leader said she has run a straight-forward and honest government, and stands by her integrity.
Parliament will be dissolved on 3 October, after a number of valedictory speeches from departing MPs. The last date an election could have been held was 15 November.
Radio New Zealand's political staff say the election date comes as no great surprise, having been tipped as the likely date for some time.
They say the Government would have taken into account events such as a major rugby test on 1 November, and the United States presidential elections 4 November.
They say the Government is also mindful of tax cuts taking effect on 1 October, and will want people to have had the benefit of those for some weeks before polling day.