Mana Party leader Hone Harawira says a vote for him in the September election will be a vote to return the foreshore and seabed to Maori.
The Mana and the Maori parties are joining forces to try to win back the Maori seats they lost at the 2014 election.
Mr Harawira, Kim Dotcom's former Internet Party ally, will this time stand for Mana in Te Tai Tokerau with no Maori Party candidate in the seat, which he lost to Labour's Kelvin Davis by around 750 votes last time.
In return, the Maori Party will stand candidates in all six other Maori seats, with no Mana candidate against them.
"Importantly, I want people to know that a vote for me is to return the foreshore and seabed into Maori hands," Mr Harawira said.
Labour's leader, Andrew Little, says Mr Harawira is dreaming if he thinks he can beat Mr Davis.
"Kelvin is a strong, competitive candidate in Te Tai Tokerau. He has nothing to fear from Hone Harawira," Mr Little said.
Maori Party co-leader Te Ururoa Flavell holds Waiariki and says the election is going to be "down to four to six seats maybe".
"And we take those seats, we're in the box seat."
His Maori Party co-leader, Marama Fox, a list MP says, "Our people don't want to see us fighting, they want to see us united".
But the agreement runs out the day before the election.
The agreement allows the Maori and Mana parties to criticise each other's policies but not attack their candidates.
1 NEWS political reporter Katie Bradford says what the two parties won't say, though, is who they would support in government after the election.
She pointed out the very reason Hone Harawira left the Maori Party in the first place was its support of the National Party.