Prime Minister John Key has again ruled out working with Winston Peters and says if New Zealand First holds the balance of power after the November 26 election, there will be a Labour government.

Mr Key said he intended leading a positive, aspirational government in a second term.

"I don't see a place for a Winston Peters-led New Zealand First in a government that I lead," he said at a press conference today.

"Historically, he has always been sacked by prime ministers. It's a very different style to mine and it's rearward-looking.

"I'm about tomorrow. I'm not about yesterday."

Mr Key said before the 2008 election he would not work with Mr Peters, a decision which was considered to have played a part in NZ First's failure to reach the 5 per cent threshold of the party vote, and disappear from Parliament.

Mr Peters is campaigning to get back in, with his party polling between 2 per cent and 3 per cent in most surveys.

Before the last election Mr Peters was involved in a scandal over party subscriptions, and Mr Key said at the time he did not want to run a government which was like a soap opera.

Mr Key is again gambling on NZ First failing to make it into Parliament, or failing to hold the balance of power if it does.

"If Winston Peters holds the balance of power it will be a Phil Goff-led Labour government," Mr Key said.

He said ruling out NZ First did not mean National would lend a helping hand to its other potential partners - Act and United Future - to ensure they kept their electorate seats of Epsom and Ohariu Belmont respectively. National would stand candidates in those seats.

Mr Peters said Mr Key was running scared.

"We usually wait until the people have voted to form a government," he said.

"Unlike money traders and junk bond dealers we do not make deals until the event has actually taken place.

"Mr Key is obviously dead scared that we will be around to stop him flogging off all our state-owned assets," he said. "He knows that we will not let National go down that path ever again. He knows that we will not let National give away the Foreshore and Seabed."

He also said NZ First had never indicated it wanted to go into coalition with any particular party.

"We also have the option of sitting on the cross-benches acting as a watchdog for the people and getting them a better deal from whoever is in government."

In a press conference this afternoon, Labour leader Phil Goff said November 26 was "the logical date" for the election. "It gives us a clear space between the Rugby World Cup and the election to campaign in."

He wouldn't rule out working with NZ First, saying "it would be arrogant to presume who will be in or out before the election".

Mr Key said he had informed the Governor-General of the election date last night and Parliament was likely to rise on October 6 and be dissolved on October 20.

Writ day would follow on Wednesday, 26 October, and nomination day would be Tuesday 1 November.

Labour Leader Phil Goff reacted to today's announcement saying his party was ready to begin the election battle.

"Labour will campaign on the issues that are affecting New Zealanders most. We know that people are worried about the soaring cost of living with prices rising much faster than wages. That will be a key issue this election."

In a press conference this afternoon, Mr Goff said November 26 was "the logical date" for the election, saying it gave Labour a "clear space" between the Rugby World Cup and the election to campaign in.

"You didn't have to be a rocket scientist to guess the date."

Mr Goff wouldn't rule out working with NZ First, saying it would be "arrogant" to rule anyone out before the voters had made their decision.