A bay of water that runs into Sydney Harbour mysteriously turned red this morning.
Locals discovered Careening Cove, beside Milson Park at Kirribilli, had changed colour.
North Sydney Council said it reported the claret-coloured water to authorities.
“Council is aware of the red water flowing into the harbour from Milson Park, and officers have investigated but have not been able to find the source,” a spokesperson said.
“We have reported it to the EPA.
“The cause of the colour is likely to be plumbers’ dye which, while alarming in appearance, is safe and non-toxic.”
The NSW Environment Protection Authority is currently investigating.
“North Sydney Council alerted us to red plumbers’ dye in a drain at Kirribilli this afternoon and we are currently investigating the potential source,” a spokesperson said.