Hawke's Bay's District Health Board has issued pollution warnings for seven of the region's recreational waterways.
Medical Officer of Health, Dr Caroline McElnay, announced yesterday that due to contamination, people should not swim at the sites - ranging from Mahia to Ocean Beach - until further notice.
Monitoring by the Hawke's Bay Regional Council identified high levels of E. coli and Enterococci in water samples taken on Monday.
The levels exceed the maximum values recommended in the Recreational Water Guidelines and indicate that at the time of sampling there were excessive amounts of faecal matter, either animal or human, in the water.
A statement said it rained heavily on Sunday night, which would have washed material into the waterways and could have contributed to the high E.coli and Enterococci levels.