Government negligence has contributed to the decline of the oceans, the Green Party says.
The Environment Ministry, in collaboration with Statistics New Zealand, has released a report saying oceans, coasts and marine wildlife are deteriorating due to increased pressure from humans.
Green Party co-leader James Shaw said the party knew the state of the oceans was bad, but were still shocked by the report's findings.
"Ocean acidification - which is derived directly from the warming oceans which is derived directly from climate change, which is derived directly from countries like ours which have got extremely high emissions per capita - just says 'look, our emissions have gone up 20 percent in the past eight years, clearly we're part of the problem'."
The government said the changes had implications for generations of New Zealanders to come and were likely to continue into the foreseeable future.