Swimmers are being warned to take a raincheck today, with several Sydney beaches likely to have been contaminated with bacteria by recent storms.

The NSW government has recommended swimmers avoid popular beaches at Manly, Tamarama, Bronte, Coogee, as well as beaches at Birdwood Park, Narabeen, Collaroy, Curl Curl, Freshwater, Queenscliff and Steyne due to “likely pollution”.

North Curl Curl and Tamarama beaches are both officially closed because of the pollution risk and dangerous surf conditions, the Sydney Morning Herald reports.

Rainfall data is used to predict pollution levels along the coast, and authorities say its possible a number of other beaches may also have been affected. Visitors are advised to “take care”. The full list is available here.

Heavy rainfall may carry debris and even faecal matter from overflowing stormwater drains, which can cause gastroenteritis and infections.

As a general rule, the NSW Office of Environment & Heritage recommends avoiding swimming at ocean beaches “for up to one day after heavy rainfall or for as long as stormwater is present”.

Its website also cites the clearest signs of stormwater pollution as water discolouration and debris in the water and on the tide line.

Daily water quality updates are available on the NSW Office of Environment & Heritage website, but live updates can be found on the Beachwatch NSW Twitter account.