Voters at 15 NSW councils in the middle of legal fights against mergers will nonetheless go to the polls this year, in elections that will cost millions and which critics say could have to be repeated within a year.

The Local Government Minister published plans on Monday for more than a dozen Sydney councils to be part of this year's local government elections.

The opposition says that holding an election for a council that could have its existence cancelled "weeks later" is an insult to voters.

"The nonsense is these councils will go through the expense of staging a democratic vote only [so they could] be told 'scratch that, you're going to be merged'," said Labor's local government spokesman, Peter Primrose. "It's a total insult".