National leader Bill English says negotiations will begin in the next few days with New Zealand First after his party won the largest share of the vote following an extraordinary election campaign.

English said he would personally discuss with New Zealand First leader Winston Peters the formation of a new government, which he promised would deliver for all New Zealanders - including those who did not vote National.

The Labour-Green bloc is also in a position to form a Government with NZ First after last night's result but English said he would not be rushing to get into ahead of Labour leader Jacinda Ardern. Negotiations were more than just a "race to make a first phone call", he said.

"Mr Peters has indicated that he does not want to be rushed. It gives us a bit of time to look at our policies, look at his policies, work out where the common ground is likely to be."

Advertisement

The key condition of any negotiations would be continuing National's economic direction - something which could clash with Peters' proposals to reform the Reserve Bank, lift Government spending, and dramatically cut immigration levels.

English refused to say what he was willing to concede to Peters, and would not rule out some of Peters' bottom lines such as migration changes or a referendum on the Maori seats.

Asked whether NZ First was obligated to go with National as the largest party, English said "we're not going to tell Mr Peters how to negotiate". But he added that National clearly had a stronger mandate and that its result of 46 per cent of the vote was an endorsement of the country's direction over the last nine years.

In his speech at the SkyCity Convention Centre, English complimented Peters on his party's "strong performance".

"Voters in New Zealand have given New Zealand FIrst a role in forming the next Government," he said, "In the next few days, we will begin discussions with New Zealand First finding common ground and most importantly taking on the responsibility of forming the kind of government that will enable New Zealand to get on with its success."

English did not rule out an approach to the Greens, but said that James Shaw's party had already ruled itself out.

He took the stage at the convention centre at 11.30pm after getting a call from Ardern which acknowledged that he had won the most votes, but did not include a concession.

Ecstatic and relieved, he was joined on stage by wife Mary, all six of his children and deputy Paula Bennett, who had earlier called National's result "extraordinary" for a Government which was nine years old.

Former Prime Minister Sir John Key, who took a risk by handing over the reins to English 10 months ago, was also in the audience.

"Just short of half of all New Zealanders voted National and 10 per cent more than our nearest rivals," English told an audience of about 1000 people.

"But it's not so much the numbers that matter, but that expression of confidence that so many people have in the direction of this proud and confident small country.

"No one expected that just three weeks ago."

English congratulated his opposite Jacinda Ardern, who brought Labour within 10 points of National in just a matter of weeks after taking over the leadership.

He urged patience, saying there was "no rush" to form a new government. But he added that he hoped a coalition could be created "reasonably quickly".

There were some downsides for National, with its support partner the Maori Party failing to get back into Parliament. English said he had "some real sympathy" for the Maori Party, and his party would have to consider how to make up for their absence from Parliament.