According to NBC News, balls of sticky black goop were first seen on Coogee Beach on Oct. 15, prompting beach closures across the area. As of Oct. 17, Sydney's famous Bondi Beach, along with Bronte, Tamarama, Gordons Bay, Clovelly, and part of Maroubra Beach, are closed until further notice as crews clean up and remove the tar balls.

Beaches in Sydney including the iconic Bondi were closed to bathers on Thursday after hundreds of black balls suspected to be toxic washed up on the city's shores.

People have been advised not to swim near or touch the debris, which may be the result of a crude oil spill or natural oil seeps from the ocean floor.