He said there were strict rules in the Broadcasting Act prohibiting the broadcast of material on radio and television "that appears to encourage voters to vote or not to vote for a political party or candidate".
The spokesman also said the commission was considering whether the song was an election advertisement which would mean any videos of the song online would have to carry a promoter statement.
Mr Watson said the commission's decision was coloured by the subversive quality of Mr Jones' video.
"Without the images overlaid, it's nowhere near as slanted, if you want to use that word, as it may be when you see it with the video."
Mr Watson spent about $800 to hire former Trinity Roots drummer Darren Mathiassen to play on the recording and then having it professionally mixed.
"I'm just trying to recoup my costs on iTunes."
Mr Key said he'd seen the video. "It was quite professionally done. It was anti-us but as a parody it was okay. I take all that sort of stuff in the spirit it's intended, it's certainly a lot more professional than the Dotcom video of people screaming and chanting at me."
Prime Ministers in pop
Norman Kirk: Big Norm - Wellington duo Ebony topped the charts and hit gold with their 1973 tribute to Labour Prime Minister Norm Kirk but missed with their 1985 follow-up Hey Mr Lange.
Robert Muldoon: Culture - Dunedin's the Knobz protested against Mr Muldoon's sales tax on locally produced records with their 1981 hit which featured an impersonation of his trademark chuckle.
John Key: Planet Key - Wellington blues guitar virtuoso Darren Watson's attack on Prime Minister John Key is given extra sting with a pungently subversive animated video.