Ice eases grip on Antarctic base

The breakup of sea ice has created new access to McMurdo Station. Photo / Supplied

New Zealand's Antarctic base is getting closer to becoming prime waterfront property as conditions in the Southern Ocean change.

The breaking-up of sea ice means the waters are now within 1km of Scott Base, providing easier shipping access.

"The last time we saw open sea in front of Scott Base was 1998," said Antarctica New Zealand chief executive Lou Sanson.

"In the ensuing time we have had these massive icebergs break off the Ross ice shelf that led to these unusual sea ice conditions in McMurdo Sound, and some of the bergs were the bergs that floated up the coast of Dunedin."

The icebergs, some of which were half the size of Stewart Island, blocked off the entrance to McMurdo Sound and led to "massive multi-year sea ice", some of which took ships 150km of icebreaking to get in.

Mr Sanson said the breakup could not be put down to climate change.