The Ministry for the Environment wants councils to test the water quality of their beaches, lakes and rivers more regularly, following a survey showing many high-profile swimming spots are polluted.
A Consumer New Zealand water quality survey suggests nearly a third of the country's most popular swimming spots are unsafe.
The survey used a five-grade ranking system, ranging from very good to very poor, and the lowest ranking was awarded to 29% of the 501 beaches, rivers and lakes it collected data on.
Only 17% of the sites were awarded the top grade of very good.
The survey said some high profile beaches such as Waikanae Beach in Gisborne have a poor water quality rating, with pollution at such high levels it is rated as a danger to health.
Councils take weekly water samples during summer, but Environment Ministry spokesperson Todd Krieble said more frequent testing needs to be done to achieve reliable results.
Mr Krieble said 100 samples over five summers are needed to get a statistically valid grade. Single sampling tends to be less comprehensive, so the preferred option is the grading system.
Consumer NZ chief executive Suzanne Chetwin says regional and local councils need to consider making testing a priority since beaches are used by a wide variety of people.
"There's a high number of people who do get sick from going to the beach, quite surprisingly high numbers."
"These are campylobacter (or) cold- and flu-like symptoms. Some people may not even realise they have been affected and could put it down to something else."
Ms Chetwin says for a country promoting itself as clean and green the beaches should be a lot safer than they are, or at least it should be clearly stated how safe they are to swim in.
The Green Party says the Government needs to take action and strengthen Resource Management Act.
Co-leader Russel Norman says the issue is an embarrassment to New Zealand's clean and green reputation.