Scientists monitoring the effects on the environment of the Rena disaster say there are higher levels of metals such as copper, zinc and aluminium close to the wreck off Tauranga.
The container ship ran aground on Astrolabe Reef on 5 October 2011 and split in half about three months later, with the stern sinking to below the water line.
The ship's insurer, Swedish Club, said a dive survey of the wreck's sunken stern and its cargo suggests many of the remaining containers carrying known contaminants have broken up and their contents have escaped.
Chris Battershill, of Waikato University, said the finding of contaminants at the wreck site was expected and early indications are that the pollution is localised.
Professor Battershill said there will be intensive monitoring for the next month to see whether the metals are going into the food chain.
Bay of Plenty Maori say they are concerned about elevated levels of contaminants close to the wreck.
Nepia Ranapia, an elder from nearby Motiti Island, says increased pollution levels are a major concern and more information is needed from experts to get a clear understanding about the contaminants.
The Bay of Plenty Medical Officer of Health says the results do not change the current advice that there is no appreciable food safety risk from the Rena.
But Awanui Black from Te moana a toi Iwi Leaders' Forum says iwi aren't convinced and a lot more sampling needs to be done.