The Medical Officer of Health is advising people in the Bay of Plenty and Lakes districts to avoid swimming in streams, rivers, lakes and harbour areas for 48 hours after heavy rain.

Toi Te Ora Public Health Medical Officer for Health Dr Jim Miller says in the 48 hours after heavy rainfall, the risk of water contamination from rural and urban run-off is high.

'Swimming in contaminated water can cause illnesses such as diarrhoea, vomiting, and skin or ear infections.

'The rule of thumb is to stay out of the water for at least 48 hours after heavy rain.

'Following the last few days of heavy rain in the Bay of Plenty and Lakes districts, swimming is not advisable.”

Dr Miller advises people to keep an eye on children to make sure children stay well away from potentially contaminated water and particularly keep them from playing around storm water drains.

Even if more than 48 hours have elapsed since heavy rainfall, people should look out for signs of contamination. "At any time, if the water looks muddy or murky, it's best to stay out of it," says Dr Miller.