Darren Watson, the writer of satirical song Planet Key, plans to remove his song from the iTunes store if the Electoral Commission does not change its stance that is an electoral advertisment.
The music video shows Prime Minister John Key in various scenes, including standing in oil-polluted water playing a guitar as an oil rig burns.
The Electoral Commission has ruled the song and music video are an election advertisement so can't be played on radio or television, or sold, without a special statement. It has given him until 5pm today to add the statement on iTunes.
Watson said he had asked the commission to reconsider, and he was also considering seeking a judicial review in the High Court.
In the meantime, he said he would remove the song from sale as he could not risk prosecution. However, he said he believed the ruling was censorship and ridiculous.
"I'm going to use the 'c' word, and I think it is censorship. A song is not an electoral advertisement and it's not an electoral programme, it's a song. The law is wrong."
Otago University electoral law expert Andrew Geddis also believes the Electoral Commission got it wrong.
"To be an electoral advertisement a message must first be an advertisement under the (Electoral) Act. There's no definition given in the Act of what an advertisement is, and I just don't think a song released by a professional songwriter in the course of his business is an advertisement."
He said there should be judicial guidance about what was covered under the electoral rules.