A highly venomous yellow-bellied sea snake was found alive on Tokerau Beach in Doubtless Bay in Northland over the weekend.
Resident Samantha Cooper posted video to the Kaitaia Noticeboard on Facebook, attracting lots of comments and reactions.
The Department of Conservation has taken responsibility for the sea snake.
DoC expert Clinton Duffy said the native species of snake, while beautiful, is deadly and is protected under the Wildlife Act 1983. It is the only sea snake that spends their entire life far from land and gives birth to live young at sea.
Duffy said that they should not be handled as one bite was likely to be fatal.
''They hunt fish and so have a powerful neurotoxin, so it doesn't matter if the fish escapes the initial attack, it will die pretty soon. But its fangs are small and right in the back of its mouth so it has to get a really good bite.'' Duffy said.
''They are considered to be natives because they made it here under their own steam.''
Duffy says the nearest population of yellow-bellied sea snakes to New Zealand is believed to be in the northern Tasman Sea.
A spokesperson for the Ministry for Primary Industries says the snakes don't provide a biosecurity risk as they are classed as native species.