The ice-bound ship, the Akademik Shokalskiy, left New Zealand on November 28 on an expedition to commemorate the 100th anniversary of an Antarctic journey led by famed Australian explorer Douglas Mawson.
It has been stuck in the ice since December 24. Its passengers include scientists and tourists, many Australian, and a Russian crew.
The Australian icebreaker the Aurora Australis was expected to reach the ship at about midnight last night.
"The ice conditions seem to have improved and there appears to be some softening and some cracks appearing," Lisa Martin of the Australian Maritime Safety Authority.
The Aurora is the third icebreaker seconded by the Australian maritime rescue agency to try to reach the hemmed in ship.