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The icebergs drifting off the Otago coast have covered 13,500km from the Antarctic's Ronne Ice Shelf.
Their journey started six years ago, when an iceberg known as A-43, 167km long and 32km wide, broke off.
It has since broken into more pieces and the largest, called A-43A, was created in May 2001. It is considered to be the parent of the icebergs off Otago.
Niwa marine physicist Dr Mike Williams said it was unlikely the icebergs would drift close enough to the Otago coast to be seen from land because they were too far out to sea and the winds and currents would keep them away.
The icebergs - two large ones and several smaller chunks - have sparked overseas interest as people clamour to view a once-in-a-lifetime occurrence.
One of the large icebergs is about 500m long, 50m wide and 60m high while the other large iceberg peaks at more than 100m high and is three times as long. They are about 100km southeast of Dunedin and are believed to be moving north at about 2km/h.
Helicopters Otago owner Graeme Gale said there had been four helicopter flights to the icebergs yesterday. It took under 30 minutes to get to the closest iceberg.
Dr Williams said the icebergs were this far north because they were in the right place at the right time and had managed to get out of the Southern Ocean and into the coastal current.
Winds had also helped but these currents and winds were pushing the icebergs away from the coast. The icebergs would continue to melt as they entered warmer waters.
When they would totally disappear was hard to estimate.
University of Otago physics lecturer and expert in sea ice, Dr Pat Langhorne said many large icebergs had been "calved" since 2000 in the Antarctic.
It was hard to say whether this was caused by climate change or whether this would bring more icebergs to the Otago coast.
Maritime New Zealand spokesman Steve Corbett said the area the icebergs were in did not have much traffic. If people wanted to go out there he warned them to check the forecast.
- OTAGO DAILY TIMES
