Councillors voted seven to three yesterday to approach local runaka to appoint two representatives on its policy committee, joining 12 elected councillors.
The iwi representatives would have voting rights.
The decision follows a nearly hour-long debate between
Cr Michael Laws expressed opposition to the move earlier in the week, calling it ''racist'' and ''undemocratic'' as the representatives would not be elected.
Cr Michael Deaker, who supported the move, said at the meeting yesterday Cr Laws was a ''very effective populist politician'' in a ''Trumpian way''.
''Everything we're doing is lawful, democratic and desirable.''
Cr Gretchen Robertson said she ''strongly supported'' the action.
''How can we speak for iwi?
''We can't interpret; we need to hear.''
Cr Ella Lawton said the decision was ''challenging'' as she believed in a partnership with iwi, but the particular move had not been properly assessed.
''How to partner and what's the right way - we haven't explored that.''
Cr Laws said it was an issue for a new council and the move would give power to runaka, but not Maori in general.
Ngai Tahu had ''no problem'' accessing the council already, he said.
The appointees would represent Ngai Tahu interests rather than Otago in general, he said.
Council chairman Stephen Woodhead said it must always look at ways to enhance its partnership with iwi.
Runaka members signalled they might appoint representatives with Resource Management Act experience, which would greatly help the council with its work, he said.
''We will still be consulting the wider community, including all Maori.
''We are not excluding anyone.''
Cr Graeme Bell said his constituents told him they were concerned about the move.
They recognised the importance of iwi involvement, but did not think it should be in the form of voting rights.
Cr Trevor Kempton said the move was not undemocratic as committee decisions had to be ratified by the full council.
Cr Doug Brown said the arrangement would only enhance the partnership with iwi.
The decision was supported by Mr Woodhead and Crs Kempton, Brown, Robertson, Lawton, Deaker and Bryan Scott.
It was opposed by Crs Laws, Bell and Sam Neill.
The timing of iwi involvement will depend on when Ngai Tahu appoints representatives.
The council also decided to revisit its memorandum of understanding with iwi, created in 2003, about what partnership actually meant.