National's Hamilton West MP Tim Macindoe has been referred to police along with Free FM in Hamilton for allegedly airing an election advertisement outside the proper period.
According to the Broadcasting Act, an election programme cannot be broadcast at any time on radio or television except during the period from August 20 to September 19. If convicted, the offence carries a penalty of a fine up to $100,000.
The radio advertisement also failed to carry a promoter statement.
The Electoral Commission referred the MP and the radio station to police this afternoon.
In a statement, the commission said: "As this matter is now with the Police, the Electoral Commission will not be commenting further."
Mr Macindoe first won the seat in 2008 with a majority of 1618 votes. Last year he was promoted to junior whip.
He was previously chief executive of Arts Waikato, and Deputy Principal of St Peter's School, in Cambridge.