New Zealand's 2017 general election will be held on 23 September, Prime Minister Bill English has announced today.

Announcing the date this afternoon, Mr English said National will take nothing for granted in its campaign and that the economy was always the central election issue.

The PM was not ruling out working with NZ First after the 2017 election, but said it was "unlikely".

He said his preference was to continue working with current partners - Act, United Future and the Māori Party.

"Together our parties have provided a stable and successful government at a time of great uncertainty in many parts of the world," said Mr English.

Photo: RNZ / Rebekah Parsons-King

Mr English has ruled out working with the Labour-Greens grouping, saying they were an "increasingly far left, inward looking grouping, with no new ideas".

In a statement, Labour leader Andrew Little welcomed the date, saying "bring it on".

"We're well prepared, our teams are in place, our plans are well advanced and we'll be working hard to convince New Zealanders we can help give them a fair shot at the Kiwi Dream."

The Green Party said there was a "real feeling for change in our country".

"At our State of the Nation event with Labour on the weekend, we showed what a credible, compassionate, progressive alternative to National looks like.

"Contrast that with what we've seen from Bill English this week - his moral compass has been swimming in circles. New Zealanders want a Prime Minister who represents our values to the world, not one who's happy to sleepwalk through a major global political moment."

Act Party leader David Seymour welcomed the Prime Minister's announcement today, saying the party was "in its best shape for years".

"Our members are gearing up for a long campaign, and following our successful School of Practical Politics, we'll have effective candidates in electorates across the country."

Mr English said Parliament would rise on 17 August, before the election.

Overseas voting will start on 6 September, and advance voting on 11 September, according to the Electoral Commission.

The last general election was held on 20 September 2014, and the latest day this year's could have been held was 18 November.

Press conference recap:

Bill English said Parliament would rise on 17 August, before the general election on 23 September.

Mr English said National will take nothing for granted in its campaign, and the economy was always the central issue in elections.

The PM said he was not ruling out working with NZ First after the 2017 election, but said it was "unlikely".

Mr English has ruled out working with the Labour-Greens, saying they were "increasingly far left".

Labour leader Andrew Little released a statement, saying "bring it on" - "We're well prepared, our teams are in place, our plans are well advanced and we'll be working hard to convince New Zealanders we can help give them a fair shot at the Kiwi Dream."

Overseas voting will start on 6 September, and advance voting on 11 September, according to the Electoral Commission.

The last general election was held on 20 September 2014, and the latest day this year's could have been held was 18 November.

Watch RNZ's live stream of Bill English's press conference here: