E. Coli has contaminated two popular water holes with the District Health Board warning the public stay out of the water until further notice.
The public have been warned not to swim in the Maraetotara Lagoon at Te Awanga and the Waipuka Stream at Ocean Beach.
A DHB spokesman said water samples taken by the Hawke's Bay Regional Council this week identified high levels of E. coli at both sites.
He said the levels exceed the maximum values recommended in the Recreational Water Guidelines and indicated that, at the time of sampling, there were excessive amounts of faecal matter, either animal or human in the water.
"The stream at Ocean Beach is not suitable for recreation, and a permanent warning sign is already in place," medical officer of health Dr Nicholas Jones said.
"However, we want to remind the public of the risks, especially given that the stream may seem like a safer swimming option for young children with warm weather forecast for this coming weekend.
"Dr Jones said that the risks at the Maraetotara Lagoon were "generally" lower, but levels of contamination have been high this week.
"Recent rainfall is only likely to exacerbate the situation," he said.
Signage is being put in place to warn potential users.
The spokesperson said the regional council would be conducting further tests once the weather settles to determine whether there are ongoing risks at the lagoon.
The regional council website reports that its science team checks 38 popular swimming and recreation spots including coastal beaches, rivers and Lake Tutira from November 1 to March 31.
"Samples are collected on Monday of each week and quality assured results will be available on the webpage by Thursday of the monitored week," the site reads.
The site also offers the advice of the "Rule of Toes."
"If it's been raining heavily, our best advice is to stay out of the water for three days," the site says.
"A handy guide is if you can't see your toes when standing knee-deep in water, then water quality is not the best for a swim."
The council said that although Clive River, Puhokio Stream Waipuka Stream are popular places, they are generally less suitable for swimming or recreational use, due to higher potential bacteria levels.
The Clive River and Puhokio stream are sampled fortnightly as they have permanent signs up warning of the health risks, its website reports.
Tutira lake is considered always unsafe for swimming or other recreational use due to the possibility of toxic algal blooms and 'duck itch', which causes irritating red bumps on the skin.
"[The council], community groups and landowners are working to improve water quality in these places," the site says.
The DHB spokesperson said people can phone the B4USWIM Safe Swimming Line - (06) 878 1368 - or check the Hawke's Bay Regional Council website www.hbrc.govt.nz for the latest water quality information.