“Please don’t swim at Lyall Bay or in the harbour until Sunday. The heavy rain yesterday caused a small overflow at the Moa Point wastewater treatment plant,” the Council wrote on Facebook.

“Warning signs have been posted at Lyall Bay and swimmers and surfers are advised to stay out of the water in the area until Sunday. People are also advised not to swim in Wellington Harbour as pollution levels in the water will be higher due to contaminants washed down stormwater drains by the heavy rain.”

Wellington City Council spokesman Richard McLean says the contamination is normal after heavy rain.

“Especially from storm waters, the problem is every bit of pollution and chemicals and oil and dog poo that’s on the streets, it normally gets washed into the drains and into the harbour, so you get a murky water quality after the rain,” he says.

Mr McLean warns the public to avoid the water in case they get sick.

“There’s a chance they could get a stomach bug,” he says.

“The water quality drops quite a lot as a result of this kind of pollution.”

And Mr McLean has advice for Wellingtonians wanting to make the most of the sunny weather this weekend.

“They can go to swimming pools, they can go and enjoy our fabulous waterfront, or they can go to beaches further out.”