A rare white humpback whale spotted in Cook Strait yesterday is thought to be Migaloo, usually seen off the Australian coast.
The whale was seen with a black humpback during the annual Cook Strait Whale Survey.
Survey leader Nadine Bott said white humpback whales were incredibly rare, with only four ever reported worldwide.
She said distinctive features on the whale in Cook Strait strongly indicated it was Migaloo.
They include the dorsal fin's shape and also distinctive spiny protuberances behind the dorsal fin. Animals with these are commonly called 'razor backs'.
Migaloo is the most famous of the white whales and another was spotted in Norway this year, said Ms Bott.
"Migaloo is thought to have fathered two white calves which have been making appearances along Australia's eastern coast."
The whale, whose name is Aboriginal for 'white fella', was first seen off eastern Australia in 1991 and has been spotted migrating from Antarctica to the Great Barrier Reef almost every year since.
A skin sample for DNA analysis was yesterday taken from the whale with a biopsy dart and will be compared with Migaloo's DNA to confirm whether it is definitely the same whale.
The analysis will also identify whether the whale is albino or whether its whiteness is due to colour variation.
The annual whale survey, a DOC partnership with OMV New Zealand, is assessing humpback whale recovery since commercial whaling ended in 1964 and is timed for humpback whales' northern migration to South Pacific breeding grounds.
It also aims to estimate the size of the humpback population in our waters.
The survey this year has also had a spectacularly high count of humpback whales with 122 spotted, as of yesterday, already surpassing the previous highest of tally of 106 humpbacks in 2012.