The boat crashed near Christmas Island where the Australian refugee detention centre is located [The West Australian]

Wayne Swan, Australia's acting prime minister, has said that a "large number of people" have been killed when a boat carrying asylum seekers crashed into rocks off the country's coast.

Swan told reporters on Wednesday that the boat smashed at Christmas Island, which is where an Australian refugee detention centre is located, and that some people have been rescued but that bodies also have been retrieved from the sea.

According to local media, federal police have said 41 survivors have been pulled out from the wreckage.

The Australian Flying Doctors service added that the death toll could be around 50 with "about 33 walking  wounded".

A survivor told Australian police there were some 70 to 80  people onboard the vessel, which appeared to be Indonesian. 

Officials also told Reuters news agency they believed most passengers were of Middle Eastern origin.

Television footage has shown the boat rammed bow first onto the rocks, splintering and sinking, and its passengers, including women and children, thrown by waves against sharp rocks.

Wreckage

The images also show people floating in the water amid the wreckage. The boat was about six to nine metres long, with a cabin covered by a sheet of fabric or plastic.

The Australian government meanwhile announced that Julia Gillard, the prime minister, will return from leave to be briefed on the situation.

Simon Prince, a local resident who lives next to the cliff where the boat crashed, told the Associated Press he was woken early on Wednesday by what he thought were cheers.

He walked outside to the cliff and instead heard cries for help from a boat just offshore.

"The engine had failed,"  he said.

"They were washing backward and forward very close to the cliffs here, which are jagged limestone cliffs, very nasty.''

"When the boat hit the cliff there was a sickening crack. All the people on board rushed to the land side, which is the worst thing they could do, but I don't think anybody could swim. I think there were about two lifeboats on board this thing,'' Prince said.

Christmas Island, located south of Indonesia, is a regular destination for boats carrying asylum seekers and is home to Australia's main offshore immigration detention centre.

Rescuers said the stormy seas and the island's jagged coastline made rescuing those on board the vessel very difficult as the island does not have a protected harbour in which to land people.

In recent years, many asylum seekers have come from Sri Lanka, Afghanistan, Iran and Iraq. Generally, they first fly to Indonesia and then continue on to Australia in cramped, barely seaworthy boats.