Almost 90 drones fell into the water of Sydney's Darling Harbour during a light festival on Monday.
The malfunction was due to "unforeseen technical difficulties", according to organisers Vivid Sydney, an annual three-week festival that features large light installations.
Two upcoming aerial displays have now been cancelled.
A Vivid Sydney spokesperson apologised for the "disappointment and inconvenience caused to attendees" and said the drone operators cancelled the show "in line with standard safety protocols".
