Hunter Water is advising people not to swim in Lake Macquarie at Warners Bay following a sewer main break on Saturday.
Hunter Water has installed signs and temporary fencing along a section The Esplanade following the burst, which occurred just after 8am.
"Our crews were able to isolate the break shortly after and our environment team has undertaken sampling," a statement from Hunter Water said.
"We're advising people not to swim in the area as a precaution for their safety."
