Kai Iwi beachgoers have been warned to be aware of falling mud rock.
Local resident John Carsons says the rock is falling at the headland of the Mowhanau Stream.
"There's bits falling all the time. People think they'll get some warning and jump out of the way," he said.
"People sit right under those cliffs whitebaiting. Personally, I wouldn't stand there.
"What is alarming is that recently debris is falling from the cliffs adjacent to the playground and the whole cliff face appears, to a layman like me, to be very unstable and likely to crush."