Scientists say it could take hundreds of years to reverse any of the damage to the Fox and Franz Josef Glaciers brought on by climate change.
The West Coast attractions had retreated rapidly over the last five years, and tour-operators could no longer take punters through on foot.
Until a couple of years ago people could walk straight up to the Franz Josef Glacier, and before April last year it was the same on Fox Glacier.
The ice had been melting since 2008, following decades of steady growth.
Glaciologist at Victoria University's Antarctic Research Centre Andrew Mackintosh said on current predictions the glaciers would become even smaller, harder to get to and less spectacular.
He said glaciers naturally advanced and retreated but they were now doing so faster - and humans were at least in part to blame.