A helicopter mission to rescue 52 passengers trapped on an icebound Russian research ship finally got underway in Antarctica after a number of failed attempts.

The Australian Maritime Safety Authority's Rescue Coordination Centre, which is overseeing the rescue, had said earlier on Thursday that sea ice was preventing a needed rescue barge from reaching one of the vessels, which would likely delay the entire operation.

But on Thursday evening, a helicopter from the Chinese icebreaker Snow Dragon landed next to the ship, expedition spokesman Alvin Stone said.

"The rescue's under way, so (there's) a little bit of joy,'' Stone said.

Expedition leader Chris Turney posted video of the helicopter's arrival on his Twitter account, writing: "The Chinese helicopter has arrived (at) the Shokalskiy. It's 100% we're off! A huge thanks to all."

The helicopter will carry the 52 scientists and tourists on board a dozen at a time to the Snow Dragon, in an operation expected to take five hours.

A barge will then ferry them 4 kilometres to the Australian icebreaker Aurora Australis. All 22 crew members are expected to stay with their icebound vessel, which is not in danger.

The Aurora will carry the passengers to the Australian island state of Tasmania, arriving by mid-January.

The long-awaited rescue came after days of failed attempts to get the passengers off the Russian ship MV Akademik Shokalskiy, which got stuck on Christmas Eve. Blinding snow, strong winds, fog and thick sea ice forced rescuers to turn back time and again.

Frozen in place

Three icebreakers were initially dispatched to try and crack their way through the thick ice surrounding the ship, but all failed. The Aurora came within 20 kilometers (12 miles) of the ship Monday, but fierce winds and snow forced it to retreat to open water.

The Akademik Shokalskiy, which left New Zealand on Nov. 28, got stuck Christmas Eve after a blizzard pushed the sea ice around the ship, freezing it in place about 2,700 kilometers (1,700 miles) south of Hobart, Tasmania.

The ship isn't in danger of sinking and has weeks' worth of supplies on board, but it cannot move.

The scientific team on board had been recreating Australian explorer Douglas Mawson's 1911 to 1913 voyage to Antarctica. Turney had hoped to continue the trip if an icebreaker managed to free the ship.