Samoan-born Mr Tua had agreed to talk to his family and his matai elders and come back to the Maori Party in the new year with a decision.
Mr McKenzie said they talked about principles and tikanga (customs) "and we are just truly aligned with Pasifika".
The Maori Party has fielded many non-Maori candidates in general seats. But next election, the party is going to campaign more strongly for the party vote among voters on the general roll rather than concentrating, as it has in the past, on winning the Maori electorate seats.
It received only 1.43 per cent of the vote last election, a little higher than Mana, Act or United Future.
The Maori Party approached Mr Tua after he made complimentary comments about the party in a television interview at the Maori Sports Awards last month.
Before that, Mr Tua had raised the possibility of becoming a politician and forming his own Pacific-based party.
He retired from boxing last month after losing to Alexander Ustinov.