An independent review of Maritime New Zealand's response to the grounding of the container ship Rena says the organisations initially struggled to function properly at its Incident Command Centre and with the Maritime Incident Response Team.
The independent review says the way Maritime New Zealand handled the emergency started to improve about five days after the grounding.
The ship ran aground on Astrolabe Reef on 5 October 2011, leaking at least 350 tonnes of oil into the ocean, coating beaches and wildlife.
The review says Maritime New Zealand needs to be better prepared, do more training, improve its administration and engage more with communities and iwi.