Residents on the south side of the of main island of the Cook Islands have called for work to stop on a land reclamation project.
The residents say fill taken from a new harbour project on the north side of Rarotonga may be toxic.
Two families say they want the government to test the landfill for toxins before they use it in Muri lagoon which is popular with tourists.
Earlier this month, a New Zealand scientist said Muri lagoon is already polluted with seepage from sceptic tanks and run off from inland farms.
Some Muri residents says they do not want to risk having the fill adding to existing problems.