Prime Minister John Key says the Tai Tokerau by-election was "an expensive waste of time".
Mana Party leader Hone Harawira won yesterday's by-election ahead of Labour's Kelvin Davis by 867 votes with the Maori Party candidate Solomon Tipene a distant third.
The result - which does not include special votes - compares to the more than 6000 majority Harawira gained at the 2008 election while standing as a Maori Party candidate.
In the build up to the by-election - which was called after Harawira resigned from Parliament in May - Key backed Davis to win.
Speaking in Darwin today, en route to India, Key said Harawira had a "very reduced mandate".
"I think most New Zealanders would think it was an expensive waste of time," he said.
"We spent hundreds of thousands of taxpayer dollars, we've ended up in the same position that we started in, and it's not really that Hone Harawira can claim victory.
"This is a very reduced mandate. We're now five months out from an election and that's when the country will really go to the polls so a bit of a waste of time."
Harawira said in his victory speech that his new party "didn't have two cents to rub together and we won."
He also criticised Key's prediction of Davis winning, saying it was not because National likes Davis, or fears Harawira but "because National fears all of you".
The Mana Party's registration was made official ahead of yesterday's voting, meaning Harawira will now qualify for extra funding as a party leader.
Harawira told TV ONE's Q+A programme today that "the power of the people" gave him victory.
"We didn't have the money, we didn't have the machine, we didn't have the advertising, we didn't have the billboards, we didn't have the flyers," he said.
Asked if a Mana candidate would be in every Maori seat in the General Election on November 26, Harawira said "that's something we've yet to talk about within Mana".
Harawira said he had tried to contact Maori Party co-leaders Tariana Turia and Pita Sharples today.
He told Q+A that "Maori people want the Maori Party and Mana to be alongside one another and alongside the people".
"If we can manage our relationship so that we're not fighting one another and focus on the needs of our people, then we might be able to bring the Maori Party and Mana together, maybe with eight seats, Mana Maori," he said.
Broadcaster Willie Jackson has been talking about standing for Mana. He told TVNZ's Marae Investigates he had been "humbled" to have been asked.
However, he said his "main concern at the moment is to get the two wakas together".
Jackson said he would like the Maori Party and Mana agree not to run candidates against each other in the seven Maori seats as that could split the vote and give Labour victory in four of them.
Asked on Marae Investigates if the Maori Party would not stand a candidate against a Mana Party candidate at the election, Sharples said "I don't think we can do that in fairness to our people".
Voter turnout for the by-election was estimated to be little more than 41% of the 32,738 people enrolled to vote.
The preliminary results are based on the 11,606 ordinary votes counted on election night, though there are more than an estimated 1900 special votes still to be counted.
The Official Results process starts tomorrow and is expected to be completed by Wednesday July 6.
Preliminary Results are:
Hone Harawira, Mana Party, 5611 votes
Kelvin Davis, Labour, 4744 votes
Solomon Tipene, Maori Party, 1026 votes
Maki Herbert, Aotearoa Legalise Cannabis Party 126 votes
Kelvyn Alp, OUR NZ, 63 votes