The Prime Minister plans to focus on his Cabinet reshuffle today once he lands in New Zealand, fresh from watching Minke whales, orcas and penguins in Antarctica.
John Key left Scott Base by helicopter this morning to catch an eight-hour flight on a United States Hercules back to Christchurch, where he was due to arrive about 5pm.
Yesterday, he said he would work on his ''minor'' Cabinet reshuffle as soon as he returned, including planning to talk to the new Speaker of the House to replace Lockwood Smith.
However, he declined to be drawn on which minister would be chosen for that job, widely speculated to be David Carter, saying there were a number of potential contenders.
He also hinted it was likely Nick Smith would return to Cabinet.
Yesterday, Key and wife Bronagh spent much of the day out visiting some of New Zealand's scientific projects as well as enjoying its stunning sights and history by helicopter.
''I think to describe what we saw as breathtaking or spectacular would be akin to sort of describing the QEII as a boat. I mean words just can't justify the beauty and the landscape,'' he said.
One highlight was a helicopter flight over Mt Erebus, the scene of the Air New Zealand DC-10 jet crash in 1979 that killed 257 people.
While they were unable to see the crash site, he said it was a poignant moment to see the mountain that had claimed so many lives ''a place of great history and tremendous sadness for New Zealanders''.
''It was very quiet in the helicopter when we were up at 13,000 feet and looking into the crater and just remembering those New Zealanders who had lost their lives.''
Last night he spoke at a party at Scott Base for its 56th birthday, saying he vowed when first in Antarctica in 2007 that he would ensure families of the victims would get to visit the site if he became Prime Minister ''for closure'', which occurred in 2009.
Yesterday, the couple visited Anglo-Irish polar explorer Ernest Shackleton's hut at Cape Royds, the base for his 1907-09 unsuccessful expedition to the South Pole.
On Saturday, Key handed back three bottles of Mackinlay whisky that had been buried in ice under Shackleton's hut since the expedition but excavated in 2010 by the Antarctic Heritage Trust while undertaking restoration work on it.
The bottles, from one of three crates of whisky discovered at the hut, were sent to Scotland distillery Whyte & Mackay, the brand's owner, for analysis and replication.
Last night, the Scott Base whisky club held a tasting of the replica blend in the first Scott Base, now called the Trans Antarctic Expedition hut, which was erected by Sir Edmund Hillary and his team of Kiwis in 1957.
During Key's trip to a scientific project studying climate change at Victory Valley in the McMurdo Dry Valleys, the driest place on earth, his support crew chipped off some ice from the Victoria Glacier.
At Scott Base, the ice is nicknamed ''Christ's tears'' because it was formed thousands of years ago as it slowly made its way down the polar plateau to the glacier's terminal face.
That ice was used to mix the replica whisky, which Key heaped great praise while sampling a tipple with the club and socialising with Scott Base staff.
He said he was impressed by the calibre of scientific work underway by New Zealand in Antarctica, which held great importance for the country because of the frozen continent's major influence on New Zealand's climate and as a place to understand global warming's potential impact.
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