Council chairman David MacLeod said there was no other way to guarantee Māori representation with full voting rights at the council table.
"Māoridom know it's not perfect, we know it's not perfect, but Māoridom still want this to go through … and I don't think it is right for our council to second-guess that."
MacLeod warned that saying no would be a step backwards.
"We will dramatically affect our relationship with Māori."
Councillor Charlotte Littlewood said there had been a groundswell of change since a referendum overturned New Plymouth District Council's vote for a Māori ward six years ago.
"A ward is about representing a community of interest and having a guaranteed voice at the table. Having that Māori voice is so important."
Councillor Neil Walker said Māori from South Taranaki would effectively lose their local vote.
"About two-thirds of Māori are in New Plymouth and it seems highly likely the new councillor will come from there."
He voted against the Māori constituency, and instead proposed that the eight Taranaki iwi appoint their own representative with voting rights.
But electoral officer Dale Ofsoske said the law did not allow for an appointee with voting rights.
The proposal attracted 383 submissions, with 55 per cent in favour and 45 per cent against.
Some submitters wanted to be able to vote for local candidates as well as for a Māori seat.
Speaking for Taranaki iwi and the Taranaki Māori Trust Board, Wharehoka Wano said Māori should not lose the right to vote for multiple candidates in geographical constituencies, in exchange for a single vote for a Māori seat.
But the electoral officer advised the law forbids voting for both Māori and general constituencies.
Despite that, Wano said the iwi and trust board both believed it was time to have a strong, clear voice at the table via a Māori constituency.
"It's time for our tribal voice to add value to this important work that you do."
Ngāruahine general manager Allie Hemara-Wahanui said an onslaught of central government reforms around resource management and water services highlighted the importance of mana whenua representation.
"We are not an interest group, we are a partner in the Treaty.
"The key thing is the opportunity to have someone sit at this table who understands the views of iwi and hapū."
Ngāti Ruanui's Graham Young said Māori had for too long been oppressed by local government with limited engagement and partnership.
"Māori constituencies provide the ability to create the right balance where previously Māori remained woefully underrepresented in local government."
Mike Butler travelled from Hawke's Bay to oppose the Māori constituency on behalf of the lobby group Hobson's Pledge.
He said councillors should vote against the seat or send it to a public referendum, as only a small number of people support a Māori seat.
"When you look at the people pushing it, it's a relatively small group of people – activists, a few people in Parliament, reporters and editors."
Local Hobson's Choice member Kevin Moratti said the majority of people did not want division by race.
"There is a huge racial divide that we are creating and that is currently seething at the moment. It is very alive and is unhealthy."
Pete Ardell of the group Wake Up New Zealand said he didn't agree with representatives being chosen according to race.
"As far as I'm concerned this has gone far enough. We're all New Zealanders brown or white. We're being divided deliberately so we can be controlled."
But many Pākehā submitters supported the Māori constituency.
New Plymouth's Barbara Hammonds said Māori had been poorly served by local bodies.
"Pākehā have always been represented at the table, tangata whenua have not. A Māori constituency will guarantee a seat at the table."
Karen Venables pointed to the overwhelmingly Pākehā councillors and managers in the council chamber.
"I lived in South Africa during apartheid and do you what it looked like? What we have here: white people sitting at the table making decisions and the indigenous people, the tangata whenua, sitting back here asking for a seat."
The Taranaki Regional Council will now hold a representation review to decide the number of general and Māori constituencies, their borders and how many councillors will represent each.