Sydney’s popular Manly Beach and other beaches around the Australian city were closed on Tuesday as authorities investigated marble-sized balls of white and gray debris that had washed on shore, in the latest such mysterious incident in recent months.

Nine beaches along Sydney's Northern Beaches have closed for precautionary reasons after numerous tiny balls were found washed up on the shoreline.

All but one of the nine major north Sydney beaches which were closed this week after mysterious ball shaped debris washed up on the sands have now reopened.

Beaches in Sydney, Australia, were closed to bathers after small white and grey balls of debris washed up on the shores at the height of the summer holiday season.

Nine beaches in Sydney, including the well-known Manly beach, were closed to swimmers on Tuesday after small white and grey balls of debris washed up on the shores.

Sydney’s pumping of primary-treated effluent into the ocean makes us out of step with the rest of the world, a water engineering expert said.

Testing by authorities determined those balls were most likely the result of a sewage spill. In a post on Facebook on Tuesday, the Northern Beaches Council said they were alerted

Sydney’s popular beaches, including Manly, were closed after marble-sized white and grey balls of debris were discovered washing ashore. This marks the latest mysterious incident in a series of similar occurrences in recent months.

Nine Sydney beaches have been closed after ball-shaped debris was found in the sand, following similar objects being found in the eastern suburbs last year.