((Adds comment from Chinese captain, Australian rescue agency)
SYDNEY/MOSCOW, Dec 28 (Reuters) - A Chinese icebreaker trying to reach a Russian ship trapped in Antarctica has been halted by thick ice within sight of the stricken vessel and an Australian ship was now trying to help, an Australian maritime rescue agency said on Saturday.
The Snow Dragon was one of three icebreakers sent to free the MV Akademik Shokalskiy, which became stranded far south of Tasmania on Tuesday in ice driven by strong winds.
"Since the thick ice exceeds the ship's icebreaking capabilities and an upcoming cyclone will exacerbate icy conditions, we have to temporarily stall the ship," Snow Dragon captain Wang Jianzhong told the Xinhua news agency.
The trapped ship, the Akademik Shokalskiy, left New Zealand on Nov. 28 on a privately funded expedition to commemorate the 100th anniversary of an Antarctic journey led by famed Australian explorer Douglas Mawson.
The ship's 74 passengers include scientists and tourists, many of them Australian, and what the Russian Foreign Ministry said were 22 Russian crew members.
The Australian Maritime Safety Authority (AMSA), which is coordinating the rescue, told Reuters that the Snow Dragon would remain on standby until the Australian icebreaker the Aurora Australis reaches the MV Akademik Shokalskiy.
The Snow Dragon has a helicopter on board that can be used to rescue passengers if the Aurora Australis can not break through the ice, said AMSA spokeswoman Lisa Martin.
"The Aurora Australis is expected to arrive at the scene Sunday evening. It's pretty slow going out there," Martin said.
The third icebreaker, a French-flagged ship, is no longer involved in the rescue.
Chris Turney, an Australian professor who helped organise the voyage on the Russian ship, earlier posted a photograph apparently showing the Chinese vessel, a speck on the horizon beyond an expanse of ice.
"Everyone well," Turney said via Twitter on Saturday.
The Russian embassy in Australia has been in constant contact with the captain and said everyone on board was in good health and there was "no threat to their lives or safety".
The ship is trapped some 100 nautical miles (185 km) east of French Antarctic station Dumont D'Urville and about 1,500 nautical miles (2,800 km) nautical miles south of Hobart, Tasmania. (Reporting by Alexei Anishchuk in Moscow; Kazunori Takada in Shanghai, Lincoln Feast in Sydney and Morag MacKinnon in Perth; Editing by Toni Reinhold and Robert Birsel)