Public transport campaigners want a second harbour crossing to be the hot issue in this year's mayoral campaign.
A Transport Agency plan for a road-only second crossing has raised concerns.
Leroy Beckett from climate change movement Generation Zero says it is an issue voters will be passionate about.
"We think it's outrageous that anybody is looking at a second Waitemata crossing that is only for cars," Beckett says.
"At best we're only going to get buses on there. They're not thinking long-term about this."
Details on the road-based option were released under the Official Informations Act.