A giant iceberg, 115sq km in size, moving slowly from the Antarctic has been spotted on satellite images and is about 5000km from Dunedin.
The iceberg, known as B17B, was travelling roughly east, following the main ocean currents, about 1kmh, National Institute of Water and Atmospheric Research (Niwa) oceanographer Dr Mike Williams said.
"It'll take months before it might get to New Zealand."
Last month, people were excited when icebergs came as close as 280km to Dunedin, but the latest iceberg was much larger, he said.
Its size made it much easier to track by satellite.
"In comparison, it's huge."
Australian Antarctic Division glaciologist Dr Neal Young spotted the large iceberg using satellite images taken by Nasa and the European Space Agency.
When first seen, it was 140sq km, but it was gradually breaking up as it drifted from the Antarctic, he said.
The iceberg was roughly 1700km south-southwest of Perth, Australia, and was significant in that it had drifted so far north while still largely intact, Dr Young said on the division's website.
"It's one of the biggest sighted at those latitudes."
As the water warmed up, the iceberg was thinning and slowly breaking up. The resulting icebergs measured up to several kilometres in length and were spread over more than 1000km of ocean, Dr Young said.
B17B was named after the area from which it calved off, the eastern end of the Ross Ice Shelf, nearly 10 years ago.
Several other massive icebergs also calved off in the area.
Most of these drifted out of the Ross Sea and began to head westwards round the Antarctic coastline, but many became trapped in "fast ice" for several years in an area off the Mertz Glacier.
The iceberg was expected to continue tracking in a more easterly direction, he said.
As to the fate of last month's icebergs, he expected most would have broken up and melted by now.
Many had got down to a size that was difficult for him to detect with the systems he was using, he said.
