The creators of the satirical video Planet Key are going to court to try and get a ban on it overturned.
The Electoral Commission has declared it an election advertisement meaning it cannot be played on radio, television or online without a statement declaring the writer Darren Watson is a promoter.
Mr Watson's lawyer, Wendy Aldred, said the commission had not taken Mr Watson's right to freedom of expression into account.
Public law specialist Hayden Wilson of Kensington Swan said the court could decide to overrule the commission.
He told Radio New Zealand's Nine to Noon programme an argument will be made that that less weight should be put on the aspect of encouraging or persuading people to vote, in order to give maximum effect to freedom of expression.
"A court may well decide that that's an appropriate interpretation - it's certainly an available interpretation."
Proceedings will be filed in the High Court this week and Mr Wilson said he would expect the musician to seek a court hearing before the election.