The Auckland Council is advising people not to swim at 16 of the region's beaches today.

Photo: RNZ / Nikki Mandow

On its Safeswim website, warnings of low water quality apply to those beaches, which means there's a moderate to high risk of infection.

Another 28 beaches have orange warnings, which means a low to moderate risk of infection.

The council has previously said that after heavy rainfall, wastewater mixes with stormwater pipes and flows out to sea.