The Cook Islands Environment Services says contaminated soil at Titikaveka is being dug up and transported further along the coast for treatment.
Information officer, Tu Tangi, says after consultation with New Zealand scientists and soil experts, it was advised that the soil be turned over on a regular basis and exposed to the sun.
He says this way most harmful chemicals would be neutralised.
It was also advised that any treatment be done at a distance from people so the soil has been returned to Vaimaaga, from where it came.
Mr Tangi says they still haven't been able to determine what's causing the problem but there have been suggestions that it could be a missing drum of ethylene di-bromide or substances like paint which could have leaked.
"We've got very loose leads to go on and we have appealed to the public that if they know of anything or they have any knowledge about dealing with toxic chemicals, to give us a hand in trying to determine what the main cause of this is. But, at the moment, we have nothing for certain."
Mr Tangi says further soil samples have been sent to New Zealand for testing and sand is being placed in the trench at Titikaveka.