Mr Key spelt out his intentions to reporters after a victory speech in which he promised to lead a government for "all New Zealanders" that would unite the country in troubled economic times.
National, with 59 seats, is strong enough to govern with just the ACT Party and its five seats.
However Mr Key will offer a cabinet post to United Future leader Peter Dunne and said last night he intended involving the Maori Party.
"We intend to have discussions with Rodney Hide and Peter Dunne, Tariana Turia and Pita Sharples," he told reporters.
"I've always argued I want to form a long-term government and I believe we can actually form a relationship with the Maori Party which, long-term, can be very important for National.
"Let's just see how that goes. We'll take that one step at a time and see if they want to form a relationship with us.
"Turia was very warm, she said she appreciated the call and `see you Monday'."
Mr Key said his deputy Bill English, and third-ranked MP Gerry Brownlee, would fly to Auckland tomorrow to prepare for talks with potential support partners on Monday.
He said ACT leader Rodney Hide would be the first cab off the rank, but he hoped for speedy talks with the other leaders as well.
Mr Key said it felt fantastic to be prime minister elect.
"Fantastic and it's the result of an enormous amount of hard work."
He said outgoing Prime Minister Helen Clark was very gracious when she called to concede the election.
"She said `I've thoroughly enjoyed the job. I wish you the very best. It was a good campaign'."
Miss Clark did not reveal she intended resigning as leader of the Labour Party, but Mr Key said he was not surprised.
"Not in one sense, I mean she's had a glittering career for 27 years, nine years as PM, I think the fifth-longest serving PM of New Zealand and I think she's done a remarkable job.
"She has done us proud on the international stage."
Mr Key said he was confident National could steer the country through tough economic times.
"I'm very confident we can work our way through it. I'm very confident about our policies, our positions, they were fully costed.
"We always took a responsible view that it was going to be pretty tough conditions and you can see that at the moment. It will be pretty tough in the next year."
Mr Key was mobbed by supporters and media last night when he arrived at National's election party.
However he was surrounded by a heavy security presence of about 10 diplomatic protection squad officers.
About 1200 supporters cheered rapturously to a triumphant speech from Mr Key in which he promised to lead a government that united the country.
