The Bay of Plenty based coastal research team, Te Mauri Moana, which has been analysing the negative effect of oil from the container ship Rena on the environment, released its initial findings on Thursday.
About 350 tonnes of oil was spilled when the 37,000-tonne container ship hit Astrolabe reef off Tauranga on 5 October 2011.
Chris Battershill, who has been leading the team, says extensive tests have been carried out on a range of kaimoana important to local Maori, including tuatua, pipi, paua and kina.
He says more than 30,000 samples were collected and analysed.
Dr Battershill says test results show the level of toxic elements from fuel oil in kaimoana has dissipated.