The writs have been issued confirming the Mt Roskill by-election will go ahead on December 3.
Governor-General Dame Patsy Reddy formalised the process by directing the Electoral Commission to receive nominations by November 9, ahead of the election next month.
A number of candidates have already been announced including National list MP Parmeet Parmar and Michael Wood for Labour.
The newly formed People Party will stand Rohan Nauhria while Auckland lawyer Adam Holland is set to run as an independent after missing out in the Auckland City Council elections.
The by-election is necessary after incumbent Phil Goff was elected as Auckland Mayor last month.