A centre-right ticket has called in the lawyers over a mix-up at council offices which led to two candidates standing for the same seat.
Auckland Future's Viliami Tiseli was meant to be nominated for the local board but was instead nominated to stand against the group's sitting councillor, Denise Krum, in the single-seat Maungakiekie-Tamaki Ward, Radio New Zealand reported.
The group said staff at the Manukau Service Centre gave Tiseli the wrong form.
It is now seeking legal advice.
If the nomination could not be withdrawn before public notices are sent out next week, Tiseli's name would appear next to Krum's on the ballot paper.