A proposal from the Compromis party would give town halls the option of letting motorhomes stay.
The Federacion de Campings criticised a proposal it argued could see public bodies compete unfairly with legal campsites.
“We have to spend money on sites, taxes, upkeep and staff,” protested Federation president Juan Delgado.
“We would not object to town halls providing suitable areas. But we would if they charged much less without complying with the same conditions,” he warned.
Camping regulations have the consensus of the sector, argued PP tourism spokesman Fernando Pastor. Compromis argues the initiative merely responds to the growing popularity of caravanning by distinguishing between parking and camping.