A Cook Islands group opposing changes to the Rarotonga water system claims the government is adding chemicals to the water without a permit.
Te Vai Ora Maori filed a complaint against the government, but the deputy prime minister Mark Brown had moved to dismiss it.
The Cook Islands News reported the NGO made the complaint to the National Environment Service, saying the government had dosed the public water supply with the coagulant, poly aluminium chloride.
Mr Brown said this was not the case, they were not using this chemical and they would follow due process by notifying the landowners before any dosing did proceed.