The Food Safety Authority is waiting for the findings of a study into how muttonbirds may have been affected by radioactivity before advising people not to eat them.
The birds could have been exposed to radioactive material in Japan.
Initial tests on birds and marine life near the stricken Fukushima nuclear plant showed extremely high levels of cesium 137, an element that strongly increases the chances of getting cancer.
Muttonbirds are due to return to New Zealand over autumn. They were within 20km of the plant at the time of the tsunami and earthquake on 11 March.
US investigator Josh Adams says preliminary results should be known by April, just as the harvesting season gets under way in the Titi islands, off Stewart Island.