Nine Sydney beaches have been closed on Tuesday (AEDT) after small white balls washed up on shore.

The Environmental Protection Agency alerted the Northern Beaches Council to the unusual debris.

Samples were being collected for testing and the council would work closely with the EPA, it said.

“So far, most samples identified are marble-sized with a few larger in size,” said the council in a release.

“The council is organising the safe removal of the matter and is inspecting other beaches.”

Beachgoers were advised to avoid Manly, Dee Why, Long Reef, Queenscliff, Freshwater, North and South Curl Curl, North Steyne and North Narrabeen beaches.

The public was advised to keep away from the material during the clean-up.

Anyone who notices this kind of debris on other beaches is encouraged to contact Northern Beaches Council on 1300 434 434.

In October last year several Sydney beaches were littered in black balls that were originally thought to be tar.

Testing revealed fatty acids from cooking oils, soap and skincare products, as well as petroleum hydrocarbons, alongside hair, food waste and other naturally decomposing substances.

They likely came from a source of “mixed waste” involving hundreds or even thousands of different materials, the NSW Environment Protection Authority said at the time.

The balls were first found at Coogee and then appeared on several more beaches.

About 2000 were picked up in an emergency clean-up operation.

Testing of the balls was conducted by the NSW Environment Department and University of NSW scientists.

Sydney Water confirmed it had found no issues with the operation or with maintenance on wastewater facilities near the beaches at the time.

Analysis of weather patterns in the lead-up also revealed no conclusive information.