The Mayor of Invercargill is concerned Labour's education plan will destroy the southern town.
The party, currently leading in the polls, will introduce a year's free tertiary education if elected - rising to three years if the party wins successive elections.
But Tim Shadbolt fears that will render one of Invercargill's main attractions for youth - its zero fees policy - obsolete.
"In 1993 when I was first elected as Invercargill's Mayor, we were the fastest declining city in New Zealand or Australia," he wrote in an open letter published by Stuff on Saturday.
"Then thanks to Penny Simmonds, her senior staff and board members, the Southern Institute of Technology (SIT) introduced a brilliant Zero Fee Scheme."
The scheme saves students willing to move to the colder, southernmost part of the country thousands of dollars.
Between 2006 and 2013, the city grew 2.7 percent. It now has more than 51,000 people.
"Labour's plans will totally undermine Invercargill's marketing edge and our innovative point of difference," says Mr Shadbolt.
But he has a plan to keep Invercargill ahead - make rent free for students, but paid for by the taxpayer.
"That will help us maintain our student numbers and take a little pressure off the housing crisis in our larger cities."
He says SIT has spent millions on apartments, and would like the Government to chip in dollar-for-dollar.