Beachgoers at Piha are being forced to defecate in the sand dunes because the public toilets are closing before many head home.
The toilets are currently locked up at about 8pm in the evening, a time when many families watch the sunset.
Piha local Bobbie Carroll said that left people with no place to relieve themselves once it was time to head home.
She said while human waste wasn't often found in the sand dunes, it was still unacceptable.
Attempts to alert to find a solution had proved fruitless, she said, because Auckland Council had refused to act for fear of vandalism.
"I don't know where they get that from, but that's what they say," Carroll said.
"The question is, do you want to deal with possible vandalism or hundreds of people out here with no toilets to use?"
Fiona Anderson from the Piha Camping Ground said she was in charge of locking the toilets up until 2010, when Auckland became a super city.
When that happened, the council decided a security firm should be in charge of locking up, she said.
Anderson said she would be happy to go back to the old way of doing things with no extra cost to the council.
Campground staff often let beachgoers use their toilets when the public ones were locked, but not everyone knew about that, she said.
"People are, you know, either asking to use people's toilets, or they're just peeing in a bush, or going behind a car, or doing whatever."
In a statement, Auckland Council said it was concerned to hear about the situation and was working to rectify it.
"We'll have portaloos out at Piha by Friday morning and will be arranging for a cleaning crew to head out there and clean existing facilities," it said.
"We will need to review the number of facilities available in the area to ensure these unsatisfactory situations don't continue."