Fecal matter is floating in New Zealand's Ocean Beach stream and swimmers have been warned to stay away from the water.

Authorities said the Waipuka Stream goes into the beach beside the popular swimming spot. Signs have been put up to warn bathers of water contamination and potential risks to health.

Dr Caroline McElnay, a medical officer of Hawke's Bay District, has issued a warning for the public not to swim in contaminated waters along the Waipatiki Beach stream and the lagoon near the Esk River.

The Hawke's Bay Regional Council has been monitoring the quality of water and found high levels of E.coli bacteria. The amount of bacteria exceeds the maximum values allowed by the Recreational Water Guidelines. When the council examined the water samples, high amounts of human and animal feces were observed.

The district council has immediately placed warning signs in specified areas. On Jan 1, officials declared the Waipuka Stream, Lake Tutira and the Puhokio Stream at Wainamara Beach as areas with disease risk.

Health protection officer Cameron Ormsby said E.coli is not considered harmful by itself but when it is detected, it is usually a sign that fecal matter is present. Mr Ormsby added that the Ministry of Environment usually has specified safe levels of bacteria. When bacteria levels exceeds the standards of the Ministry, people who will swim in contaminated waters will have a greater risk of developing ear, eye and skin infections as well as stomach illness.

According to Mr Ormsby, the spike in E.coli may be caused by heavy rains washing away sheep and cow droppings into a river or ocean. The exact sources of pollution are still being investigated.

The Auckland Council has also placed warning signs around another popular swimming spot in Judges Bay after high levels of bacteria were discovered in routine tests. A monitoring programme tests 63 beaches in Auckland to assess quality.

Marcus Herrmann, the regional and environmental control manager of Auckland Council, told media they have yet to confirm the source of contamination. Mr Herrmann clarified the beach is not closed but advised against anyone swimming in the water. The warning signs will only be taken down once the council will get normal readings.