Staff who work for the United States Antarctic Programme (USAP), based in Christchurch, are among those missing following yesterday's devastating earthquake.
The USAP, which is managed by the National Science Foundation (NSF), said on its website it had accounted for 60 percent of the people in the program who were in New Zealand when the earthquake hit.
"NSF is deeply concerned about the welfare of those people affiliated with Antarctic Program who, as yet, have not been accounted for and remains hopeful that they will be discovered to be safe and sound," the statement said.
Many of those unaccounted for may be on personal travel within New Zealand, and not necessarily in Christchurch, the statement said.
NSF also expressed sympathy to the people of Christchurch.
"Our thoughts and prayers are with the people of Christchurch and New Zealand," NSF polar programs head Karl Erb said.
"Many of us have friends and family in that beautiful city, and we are heartbroken over this tragedy," Mr Erb said
"We are doing everything possible -- and will continue to work diligently -- until all of our folks are accounted for."
USAP also said it was reviewing its flights to Antarctica.
NSF uses Christchurch airport to fly its personnel to Antartica and also maintains offices and other facilities in the city.
