The National Party wants Labour to clarify if it will continue to support a bill that would change Rotorua's electoral rules, despite warnings from the attorney general.
The bill would allow the council to be comprised of three general seats, three Māori seats, four seats at large, and the mayor.
It was prepared by Rotorua Lakes Council and adopted by Rotorua-based MP Labour MP Tāmati Coffey.
However, a report written by the Attorney-General David Parker has said the bill is discriminatory.
The bill creates a disparity in the number of people represented by each ward council member, the report said.
"The proposed representation arrangement would make the number of council members for the Māori ward disproportionately higher than the number of council members for the general ward, in comparison to their respective populations.
"This discriminates against electors who are on the general roll and ... those who are non-Māori and cannot change rolls in future."
National MP Paul Goldsmith said it would be terrible for New Zealand if the bill became law.
"I think they should drop the bill, full-stop. Also, the minister of justice or the prime minister should stand up and clearly state what they believe in when it comes to voting rights in this country, because it is confused right now.
The bill was supported at first reading by Labour, the Greens and Te Pāti Māori.
Māori Development Minister Willie Jackson has since told TVNZ's QnA programme he supported Parker's report.
"Obviously there's been some mistakes made," he said.
He put those down to an "overly enthusiastic council".
A government spokesperson said the Rotorua Lakes Council and select committee need to consider the implications of the attorney general's analysis.