The debris forces the closure of nine beaches

Months after mysterious black balls forced the closure of some of Sydney’s most famous beaches, small marble-like debris has started washing up on the city’s shores again.

The balls – this time in gray or white – have prompted councils to close nine beaches, including the popular Manly and Dee Why, while authorities investigate.

Eight beaches, including Bondi, were closed for several days in October and a massive clean-up was ordered after thousands of black deposits appeared on the coast.

Tests by authorities determined that the balls were likely the result of a dirt spill.

Northern Beaches Mayor Sue Heins said the final balls “could be anything”, according to the Guardian Australia newspaper.

“At the moment we don’t know what it is and that makes it even more worrying,” he said.

“Obviously something is leaking or falling…floating out there and being dumped.”

In a Facebook post on Tuesday, Northern Beaches Council said it had been notified of the new waste by the New South Wales Environmental Protection Agency (EPA).

The agency and the city planned to collect the findings to test and inspect other beaches in the area.

Anyone who saw the balls was asked to contact authorities, the city added.

Although it was rumored to be “tar balls”, the October debris was found to contain everything from cooking oil and soap molecules, blood pressure medication, pesticides, hair, methamphetamine and veterinary drugs.

The scientists said they resembled grease, oil and grease — often called fatbergs — that build up in sewage systems.

However, Sydney Water said there were no known problems with the city’s waste systems, and authorities still do not know the source of the material, prompting some to raise concerns about the safety of the city’s beaches.

“The EPA cannot explain the source of the human waste causing the fatberg and cannot reassure the public that Sydney’s beaches are safe to use,” state politician Sue Higginson, of the Green Party, said in a statement in December.