Thousands of “disgusting” sticky black balls that forced the closure of several Sydney beaches are made of human-made waste, scientists have discovered. The foul-smelling balls, which were first discovered on Sydney's Coogee Beach in mid-October were initially thought to be tar from an oil spill.

The golf-ball-size debris that led to beach closures across the Australian city was not tar balls as first thought, but was instead made up of decomposed cooking oils, hair and food waste.

Disgusting’ black balls which washed up on multiple Australian beaches have been identified as an odd concoction of substances. Last month, beaches in Sydney were closed as authorities looked into the bizarre black balls which washed onshore.