An informal report circulating in the Cook Islands claims that tap water on Rarotonga is filthy and potentially dangerous to health.
The Cook Islands Ministry of Health is now trying to determine the validity of the report from the Rarotonga-based Better Health Research Centre.
The Centre claims the water supply is rife with parasites, bacteria, pathogens and toxins.
Doctor Rangi Fariu, the ministry's director of community health services, says he is perplexed by the claims, which have been circulating via email this week.
But the Centre owners, David Norgren and Richard Wachter, say it's accurate, although it only confirms traces of the listed pathogens and bacteria, not whether the levels are harmful.
The health ministry's chief health inspector Tangata Vaeau says the report is probably not accurate and he advises people not to be alarmed by its content.
He says his own regular testing of Rarotonga's water supplies has not shown that it's dangerous to health.