Newstalk ZB is facing prosecution under electoral laws after Labour Cabinet minister Shane Jones and New Zealand First leader Winston Peters put in a pitch for the party vote while acting as talkback show hosts.
The Electoral Commission said the radio network breached the Broadcasting Act, which prohibitselection programmes on radio or television except in specific circumstances.
It has referred the case to the police to decide whether to prosecute - which could see Newstalk ZB facing heavy fines.
It has also referred Mr Jones' sign-off comment of "vote Labour - see you in November" to police under the Electoral Finance Act because there was no authorising statement.
But Mr Peters was let off, because his suggestion people give their party vote rather than candidate vote to NZ First was in response to a question.
The network's general manager of talkback programming, Bill Francis, said the decision lacked common sense and had serious implications for other media outlets. He said the programmes aimed to entertain and the comments were only a few seconds of broadcasts spanning 3 1/2 hours.
"In each case, the comments were one-liners, throwaway lines. Common sense has not prevailed."
The commission said the talkback shows by Mr Jones and Mr Peters in June, although aimed at entertaining, breached the Broadcasting Act because they were "election programmes" once the pitches were put in for votes.
If police prosecute, Newstalk ZB could face fines of up to $100,000 under the Broadcasting Act and $10,000 under the Electoral Finance Act for broadcasting the programmes.
The commission said the shows did not fall within the ambit of news or current affairs, which are exempt from restrictions on political coverage.
Under the Broadcasting Act, election-year party political broadcasts can be made only in set circumstances, such as under the "broadcasting allocation" given to each party.
