Mysterious black globules that washed up on a beach in eastern Sydney are oil-linked “tar balls,” local authorities say. 

Randwick City Council said preliminary tests indicated the material – which peppered Coogee Beach and were subsequently also found on Gordons Bay Beach – was a “hydrocarbon based pollutant which is consistent with the makeup of tar balls”. 

Tar balls are formed when oil comes into contact with other debris and water – usually as a result of oil spills or seepage. 

Lifeguards discovered mysterious, black, ball-shaped debris washed along Coogee Beach earlier this week. Photo / Randwick Council 

Both Coogee Beach and Gordons Bay Beach remain closed amid a clean-up to remove and dispose of the thousands of spheres the size of golf balls. 

“Our community is rightfully very protective of our natural environment and this has been a very concerning incident,” Randwick mayor Dylan Parker said. 

“Our priority as a local council is to keep people safe and protect as far as possible our coastal and marine environment.” 

Parker said a specialist waste removal contractor was systematically removing the debris from the beaches and the process would likely continue on Thursday. 

Local authorities remain unsure about the scale or origin of the pollution incident, he said. 

People were advised on Tuesday not to touch the debris at Coogee Beach and more examples were found at Gordons Bay Beach on Wednesday.