Sydney beach closed...The estimated oil waste 'black ball' is flooding in.

A number of black ball-shaped substances believed to be chunks of oil debris flooded several beaches in Sydney, Australia, prompting authorities to close the beaches and clean them up.

According to local media on the 16th, hundreds of black lumps the size of golf balls flooded Sydney's southeastern Coogee Beach from the afternoon of the previous day.

This phenomenon was also found on Gordon's Bay Beach, an aquatic reserve, and Wedding Cake Island, 1km from Coogee Beach, later in the day.

Randwick City Council, which has jurisdiction over Coogee Beach, closed the beach after warning people not to touch the material for safety.

Authorities have also launched an investigation with the Environmental Protection Agency to determine exactly what the material was and where it came from, carrying out a clean-up operation.

Local media reported that the material appeared to be a lump of so-called 'tarball' of oil debris.

Tarballs are made when oil comes into contact with plastic or water, mainly on nearby beaches when oil leaks occur in the sea.

The city council said beach cleanup work is needed for the time being, adding, "It looks like we can reopen in a few days."