Internal Affairs Minister Chris Tremain wants to know why a Northland man was able to contest the Far North mayoralty after being convicted of serious sex and violence crimes against his family.
Prominent farmer and anti-Treaty activist Allan Titford was on Wednesday jailed for 24 years on a raft of charges including rape and arson.
In sentencing Titford at the Whangarei District Court, Judge Duncan Harvey said the 53-year-old had subjected his wife and family to violent abuse in a "reign of terror" that dated back to 1989.
Titford was convicted almost two months ago of 39 offences but ran for office in October's local body elections while in jail awaiting sentencing.
Convicted prisoners cannot register on the electoral roll, let alone stand for office, and Mr Tremain wants to investigate further.
His concern is that the 414 people who voted for Titford in mayoral elections held on 12 October were supporting a man whose candidacy could have been illegal.