The DNA results are in and a white humpback whale spotted in Cook Strait last winter has been confirmed as the famous Migaloo, usually spotted near Australia.
It is the first time Migaloo -- an Aboriginal word meaning 'white fella' -- has been spotted in New Zealand waters. He was seen on July 5 by researchers on the annual Cook Strait Whale Survey.
White humpbacks are extremely rare -- there are only four reported in the world.
A skin sample was taken from the whale and DNA analysis by Oregon State University in the US has matched it with Migaloo's genetic profile.
At the time, Cook Strait Whale Survey leader Nadine Bott said distinctive features on the white whale, including its dorsal fin, strongly indicated it was Migaloo.
"I was confident it was Migaloo but it's good to have it supported by DNA results which give us 99.99% certainty it was him," Ms Bott says.
She adds that spotting Migaloo supports research findings that humpbacks seen in Australian waters move through New Zealand waters too, perhaps even more so than originally thought.
"This has been indicated particularly by matches of photos of humpback whales seen during our survey with photos of humpbacks off eastern Australia," she says.
"Confirming it is Migaloo helps us in learning more about humpbacks in South Pacific waters."
Migaloo was first seen off eastern Australia in 1991 and has been seen there almost every year since. He is thought to have fathered two white calves which have also been spotted splashing about along Australia's eastern coast. One calf was named MJ, short for Migaloo Junior.
Another white humpback whale was spotted in Norway last year.
The annual Cook Strait Whale Survey is assessing humpback whale recovery since commercial whaling ended in 1964. It has been running for 12 years.
Last year's four-week survey counted a record 137 humpback whales, which is an encouraging indication their numbers are increasing in New Zealand, the Department of Conservation says.