The Maori Party has three MPs and although National does not need them to govern, Mr Key has said he would like to work again with the party.
Co-leader Tariana Turia told TVNZ's Q+A she would be looking for more than "short-term gains" which, besides getting support for Whanau Ora, was what the party had negotiated in 2008.
"This time we'll be looking at some structural change, because we think that in the end, that's where we'll get the most gains. Because if you go for short-term gain, you don't really change anything."
In 2008, the party secured support for Whanau Ora and a review of the Foreshore and Seabed Act which led to a repeal and a constitutional review.
Mrs Turia raised two potential talking points in any deal - overhauling the role of Te Puni Kokiri, the Ministry of Maori Development, and a Treaty Commissioner.
On election night, her co-leader Pita Sharples was pushing the same message - although he used the term "transformational" change.
"I want you to know that the Maori Party this time around will be determined to work in terms of transformation of our people instead of just getting gains here or reviewing this and reviewing that."
It does not come without risks for the party. Dr Sharples said the Maori electorates had sent his party a perplexing message.
"People do not like us going with National, that was the mood that was put out there," he said, even though recent polls had shown Maori supported the party being in government.
The results showed that misgiving, with Labour making strong gains in the Maori electorate seats.
Labour, the Maori Party and Mana all stood candidates in each of the seven Maori seats. Six of the sitting MPs were returned.
However, in a devastating loss for the Maori Party, Labour's Rino Tirikatene (39) beat one-term MP Rahui Katene in Te Tai Tonga.
Labour's Shane Jones also took Dr Sharples close in his electorate race, as did Kelvin Davis, whose list placing was too low and who now finds himself out of Parliament after giving Mr Harawira a scare at the Te Tai Tokerau by-by-election and eroding the Mana leader's majority to 874 votes.
In 2008, Mr Harawira won with 60% of the vote. This time it was 40%.
Yesterday, political commentator John Tamihere said on TVNZ's Marae Investigates - where all seven MPs appeared on a panel interview - that overall Labour's performance should be read as "resurgent" in the seats.
Without special votes counted it won 40% of the party vote.
Hauraki-Waikato Labour MP Nanaia Mahuta said Labour could not rely on swings to win the seats. It was clear her party was not the winner, she said.
"I think a divided Maori vote in the Maori electorates causes a lolly scramble for National to pick off who the winner is and probably the winner after this election will be the Maori Party."
Labour MP for Ikaroa-Rawhiti Parekura Horomia also announced this was his last parliamentary term.
