Its unique environment was due to a large mountain range which prevented ice from pushing into the valleys.
Any snow was swept away by winds of up to to 300km/h, leaving a barren desert the size of New Zealand.
Antarctica New Zealand chief Lou Sanson said it was the biggest ice-free area in Antarctica, and held many surprises.
The Dry Valleys were so parched that seals which swam into the region 2000 years ago and died were preserved there in a desiccated form.
One mummified seal was found 1000m up a mountain, where it had attempted to clamber out of the valleys.
There New Zealand scientists have traced the very limits of life on Earth. The only living things are creatures and plants which could survive extreme cold, such as lichen which exist inside rocks.
Mr Sanson: "While many people thought it was devoid of life, increasingly we find it's teeming with microbial life, some of it of very unique characteristics.
"It is fascinating that you can find this life in an environment where temperatures during the winter can drop to -60C."
He said nematodes, or roundworms, survived because they could shut themselves down for four years and then "come back to life".
The slow-changing environment in the valleys, and the absence of top-end predators, made it an unparalleled laboratory for New Zealand scientists.
Professor Craig Cary, from the University of Waikato, was cataloguing and mapping the biodiversity in the valleys.
This would allow his staff of 16 to predict where biodiversity was richest on the continent, and eventually inform policy which could protect these regions.
Mr Sanson: "What we're looking to do on a much bigger scale is to say to other countries 'In these habitats we expect this life-form and we think these areas are going to be incredibly important for further protection of Antarctica'."
Mr Key also visited explorer Ernest Shackleton's hut at Cape Royd yesterday.
He had returned three bottles of Shackleton's whisky to Scott Base on Saturday after it had been sent to Scotland to allow a master-brewer to recreate it.
Asked whether he had wanted to reach the South Pole to match his predecessor Helen Clark, he said: "No, if it was on that basis she beat me.
"It's sort of a Scott-Shackleton type of issue."