Hone Harawira says the Maori Party is going to pay a high price now that he is returning to Parliament as the leader of his new Mana Party.
Mr Harawira won Saturday's Te Tai Tokerau by-election with a majority of 867 votes over Labour's Kelvin Davis, with the Maori Party's Solomon Tipene a poor third.
He said in his victory speech he was going to call Maori Party leaders Tariana Turia and Pita Sharples and "ask for a sit-down".
"I'm hugely pissed off with the Maori Party, make no mistake about that," he said.
"The price has to be paid by the Maori Party down the track, because the people need better."
He later told media he was thinking about getting together with the Maori Party to form some sort of alliance.
"After all, we clearly both support Maori interests," he said.
Mr Harawira said Prime Minister John Key had "thrown his weight" behind Labour and both the main parties were scared of his new Mana Party.
"Labour's been sucking off the Maori vote and the worker vote and the vote of the poor and the oppressed for many generations," he said.
"Their fear is that this is the start of the end of their control of that vote."
The preliminary results gave Mr Harawira 5611 votes, Mr Davis 4744 and Mr Tipene 1026.
Labour said Mr Harawira won the seat in the general election with a majority of more than 6000, and it had been slashed by 85 percent.
"Kelvin Davis was able to take on a Maori seat with one of the largest majorities and make it the most marginal Maori seat -- that's an amazing achievement," said Labour leader Phil Goff.
Mr Davis told NZPA the result was good news for all Labour's general election candidates in the Maori roll seats.
"It will mean a lot to them in terms of fighting their campaigns," he said.
"The Maori Party has been severely weakened and that bodes well for our candidates. I'm definitely going to stand again in Te Tai Tokerau and I look forward to locking horns again."
Dr Sharples told TV3 the result showed how dissipated the party's branches were in the electorate.
"They were Hone's branches and he had control of them...we're going to re-establish them, we have done already," he said.
"What has stood against us is the media, by calling it a two-horse race which made people think they had to vote for one or the other."
Mr Tipene said he had expected a better result, given the hard work he and his campaigners had put in.
Asked about disparaging remarks Mrs Turia made about him during the campaign -- she later admitted she had "stuffed up" by questioning his political abilities -- Mr Tipene said "it didn't help, to be frank".
But he said the party moved on from there and he was going to put his hand up to stand in Te Tai Tokerau in the general election.
Mr Harawira's aim now is to retain the Te Tai Tokerau seat in the general election and win enough of the party vote to bring several other MPs into Parliament with him.