New Zealand east coastal areas aren't out of the woods yet, with Civil Defence authorities and scientists electing keep the tsunami warning in place.

Wave activity "appears to be stabilised" at previously-reported levels, Civil Defence Emergency Management says.

The first wave has reached the Chatham Islands, after a massive 8.8 magnitude earthquake hit Chile overnight. An official tsunami alert remains in place for New Zealand's entire east coast.

There's no mucking around when you go fishing in the Chathams.