Up to 500 Denby Ward voters may have been sent duplicate voting forms, but the situation won't invalidate the vote and nobody will be able to vote twice.
Several voters in the Denby Ward byelection contacted the Northern Advocate this week after they received two identical voting forms in the mail.
Dale Ofsoske, from Election Service, which runs the byelection for Whangarei District Council, said he was aware of nine voters who had received identical voting papers, but there could be up to 500.
Mr Ofsoske said after being contacted by voters about receiving identical papers he visited the printer that produced the forms to find out how it happened.
"They printed the forms in batches of 500 at a time and it appears that one of these batches may have ben printed twice," Mr Ofsoske said.