"Len Brown's going to be less able to get his way over the next three years, that's obvious."
Newly elected Waitakere councillor Linda Cooper said the change in balance would be "interesting".
Centre-right Cooper replaced Sandra Coney, who retired from council after 12 years. "Richard Northey's gone, Sandra Coney's gone, so that's a fundamental change," she said.
The shift would hopefully bring some changes, especially to housing affordability, Cooper said. "People are hurting."
National Party member Denise Krum, who ousted long-serving councillor and former Labour MP Richard Northey to win a seat in Maungakiekie-Tamaki ward, said she intended to hold the Supercity mayor to account.
"People need to see more value for their money - where are my rates going? What's it being spent on?
"We see rates going up, a lot of things going up. Do we feel that we're getting a return on our investment?" Krum has criticised a lack of public consultation over the Unitary Plan and soaring debt levels and called for more transparency and accountability.
The 42-year-old businesswoman campaigned on wanting to put a "hand brake" on Brown's political programme.
But Brown said he wasn't particularly concerned about the new council make-up.
"I don't see much of a change in the left-right balance. I think people are coming from all sorts of interesting political backgrounds and views."
Councillors should put their political differences aside when they walked through the door and work together, he said.
"My door will be open to every single one of them. I think that we have the potential of working as strongly in this council as we did in the last, together.
"There will always be differences, but I think we'll be fine."