Kelvin Davis. Photo / Chris Loufte
This was only just ahead of Labour list MP Kelvin Davis, who was on 37 per cent.
The Maori Party's Te Hira Paenga was a distant third on 9.4 per cent.
A further 9.2 per cent of respondents said they did not know who they would vote for, and 5 per cent wouldn't vote.
General polling suggests Internet-Mana has enough party vote support to return three or four MPs but because it is polling below the 5 per cent threshold, it is relying on Mr Harawira to keep Te Tai Tokerau.
Reacting to the poll, Mr Harawira told a Native Affairs candidates' debate a poll three years ago also had the leading contenders neck and neck. "So when I see you have got it down as 38 to me and 37 to Kelvin I'm looking forward to it being 45 to 35 on the night.
"I think the people deserve to have a person who's not just prepared to speak up for them but who's prepared to stand up for them, who pushes the issues and is prepared to take it to the top."
Mr Davis told the debate that if people wanted better educational and economic outcomes, they should vote Labour. "The issues facing Te Tai Tokerau are numerous and they're severe. The Labour Party has a range of policies that will put money in people's pockets, will help them get jobs, is going to help them get warm homes and being safe, strong and secure whanau.
"If people ... want these economic outcomes they're going to have to vote for it. If they want women and children to be safe from rampant sexual and domestic violence they're going to have to vote for it."
Two weeks ago, another of Mana's top candidates, Annette Sykes, polled well behind Maori Party co-leader Te Ururoa Flavell in the Waiariki electorate in a similar survey that screened after a Native Affairs debate.
Reacting to polling showing more Northland people opposed Mana's relationship with Kim Dotcom than supported it, Mr Harawira said town halls in the region were packed when the Internet Party founder visited.
"We had more people, more Maori, come to these hui than any political party has been able to get to a political hui in 30 years."
The poll results also showed 39 per cent of respondents supported seeing a Labour government in Parliament ahead of the 25 per cent who wanted the Internet-Mana Party there.
Watch the policies of the leading parties in Te Tai Tokerau
Hone Harawira and Internet Mana
Te Ururoa Flavell and the Maori Party
Labour's David Cunliffe
And asked what should happen if the Maori Party held the balance of power, 66 per cent supported them going into partnership with a Labour-led government.
Of those polled, 97 per cent said education was the biggest issue, ahead of the cost of living, family violence, child poverty and Maori unemployment.
The poll of 500 had a margin of error of 4.38 per cent.
