A New Zealand air force plane made a rare wintertime landing on an ice runway in Antarctica today on a mercy mission to evacuate a seriously ill American worker, officials said.

Blizzard conditions eased to allow the Orion aircraft with three medical staff on board to land at the US McMurdo Station science base on the north Antarctic coast before refuelling and returning on a seven-hour flight to Christchurch in New Zealand.

An initial rescue bid on Sunday was forced to turn back because of blizzards. Temperatures at the base have been about minus 35C (minus 32F) in recent days.

Air force spokesman Squadron Leader Kavae Tamariki said the plane landed at around midday today (0000 GMT) during a brief period of daylight and clear weather, and spent about an hour and a half on the ground before taking off with the patient.

"It's going fine so far," he told The Associated Press. He said the patient was stable and would be admitted to hospital in Christchurch after the plane arrived at around 9pm today (0900 GMT).

The man's identity, exact condition and occupation have not been disclosed. He works for US company Raytheon, which provides support services - such as supplies, transportation and accommodation - for the US National Science Foundation at McMurdo.

"The medical advice is to get him out of there as soon as possible for hospital care," Raytheon Polar Services New Zealand operations manager Kerry Chuck said.

The US has more than 500 staff who spend the bleak winter - from October through March - at McMurdo each year. Flights are usually only made during the summer months, when most scientists are ferried in and out of the station. Icebreaker ships are used to bring in fuel.

A few winter evacuations of sick workers have been undertaken from Antarctica, including a dramatic midwinter flight in 1999, with blazing fuel barrels to light the runway, to pick up a US woman doctor at a South Pole station who contracted breast cancer.

Last September, an American working at McMurdo Station who suffered cardiac problems was evacuated to New Zealand by air force plane in a serious but stable condition.

A broad range of scientific research is conducted at the station, including the Antarctic sea and its marine life, the annual fight for survival of the world's largest penguin colonies, and the depletion of the ozone layer.