An Australian flight crew has evacuated a seriously ill American from Antarctica during the depths of the southern winter, completing a rare medical mission in near-total darkness and temperatures as low as minus 43 degrees Celsius.

The evacuation took place on July 31 after an urgent request for assistance from the United States Antarctic Program.

An Airbus A319 Long Range aircraft, operated by Skytraders for the Australian Antarctic Division, flew from Hobart, Tasmania, to the U.S.-run McMurdo Station and then carried the patient to Christchurch, New Zealand.

The patient was admitted to Christchurch Hospital in serious condition.

Authorities have not disclosed the person's identity or medical diagnosis.

The American was receiving treatment after the flight, and no further information has been released about their condition.

The mission had been requested on July 28, but severe weather initially prevented the aircraft from leaving.

The crew used a narrow weather window three days later, departing Hobart in the early hours of July 31 with medical personnel and Antarctic specialists on board.

The aircraft, known as Snowbird 1, reached Phoenix Airfield near McMurdo after a journey of about five and a half hours.

It landed in complete darkness, a defining feature of the Antarctic winter, as conditions deteriorated and temperatures fell to minus 43 degrees Celsius.

The flight's difficulty lay in far more than the cold.

Antarctic winter operations offer few alternatives if weather shifts or a landing becomes impossible.

Crews must account for long distances, rapidly changing conditions, reduced visibility and the performance limits of aircraft and ground equipment in extreme cold.

The aircraft carried additional fuel in case it had been unable to land and needed to return.

The runway itself required intensive preparation.

Phoenix Airfield is a compacted-snow surface rather than a conventional paved runway, so ground teams must ensure that it is sufficiently smooth and provides enough friction for a large aircraft to stop safely.

The rescue involved coordination among pilots, meteorologists, operational planners, runway crews and medical teams in Australia, Antarctica and New Zealand.

Captain Al Wallach said Antarctic missions always demand precision, but winter operations add substantial complexity.

He described the conditions encountered as being near the limits of even a specialised aircraft's capability.

Co-pilot Louise Robertson said the flight required sustained concentration, planning and calculations, with relief only coming as the aircraft approached New Zealand.

Winter evacuations from McMurdo are uncommon because the station is isolated for months by darkness, weather and extreme cold.

Its small medical facility can stabilise patients, but serious illnesses or injuries can require transport to New Zealand, the principal medical evacuation route for the U.S. Antarctic Program.

The aircraft departed Antarctica soon after taking the patient aboard, before the weather worsened further.

The successful transfer has left the patient under specialist care in Christchurch and demonstrated the international emergency network that supports research personnel on the world's most remote continent.