A scientist says the slow breaking down of the container ship Rena could pose a risk to the environment.
Since running aground on Astrolabe reef off the coast of Tauranga in October, the ship has broken in two with the stern section, containing the crew's quarters, now underwater.
The waters around the reef have almost returned to the state they were in before the ship struck the reef.
However Chris Battershill, who is surveying the impact of the grounding on the environment, says what's left of the Rena has the potential to be concerning.
In the summary of facts read out for the sentencing of the ship's captain, it was revealed that if the original fixtures on the ship, such as machinery, cabling and assorted fittings, were to be released it's likely they would be classified as contaminants.
Professor Battershill says surveys in June and on the anniversary of the Rena incident, will serve to double check what has happened to the environment.