A Whanganui beach is closed after a strange woolly substance washed up on the sand.
South Beach, near Whanganui Airport, was closed yesterday after the substance was found and workers have begun clearing the debris today.
The substance has been on the beach since Sunday evening or Monday morning as there were two layers, indicating two tides.
Wanganui District Council staff were notified on Tuesday morning and closed the beach.
Whanganui Mayor Annette Main said it was not clear where the substance had originated but it was not connected to the bypassing of wastewater to the sea.
"It appears to be mostly wool and if it had gone through the Beach Road pump station and then the ocean outfall, it would have blocked up the screening process.
"There is no evidence at Beach Road of this substance, however, we don't know where it originated."
Horizons Regional Council was now investigating and samples of the substance had been sent for testing.
Workers with trucks and machinery were working on the site to remove the substance, Main said.
The beach would remain closed while the clean-up machinery was there.
It was not known if more of the substance would wash up during the next high tide, Main said.