People are being warned to stay out of the water at Memorial Park and surrounding areas.

Tauranga City Council says a wastewater overflow occurred on 6th Avenue yesterday, which has prompted today's warning.

"Signage has been placed along the water's edge to warn the community of the potential risk," says a council spokesperson.

"The wastewater blockage, caused by a large towel and fat, resulted in sewage overflowing into the stormwater network and consequently the harbour.

"We have cleared the blockage and cleaned the overflow site. Initial water quality samples show elevated levels of bacteria. Additional testing is being undertaken with results expected next week."

Council says the warning signs will be removed once the tests confirm the water poses no health risk.

"Until then, people are urged to stay out of the water."