Channel 7 TV screengrab released by The West Australian newspaper shows the boat full of refugees being smashed by violent seas against the jagged coastline of Australia's Christmas Island. (AFP)

SYDNEY (AFP) – Three Indonesian men faced an Australian court Tuesday on people-smuggling offences related to the sinking of a ship carrying scores of asylum-seekers in which about 50 people were killed.

The trio are charged with smuggling a group of Iranian, Iraqi and Kurdish passengers from Indonesia to the remote Indian Ocean outpost of Christmas Island.

"Each of you facilitated the bringing or coming to Australia of a group of five or more people... namely a group of 69 Iranian, Iraqi and Kurdish people," Magistrate Joe Randazzo said.

The three Indonesians were on board the wooden fishing vessel which foundered in rough weather on December 15, forcing all on board -- believed to number about 90 -- into the sea.

Rescuers managed to pull 41 people from the water, including some with injuries from being pounded by floating debris, while one man managed to make it the short distance from the boat to shore unaided.

Authorities eventually recovered 30 bodies from the water but it is believed around 20 more were not able to be recovered.

The three men -- named in local media as Hadi Han, 22, Abdul Rashid, 60, and Supriadi, 32 -- appeared briefly in Perth Magistrates Court but were not required to enter a plea.

"They're very unhappy. It's a total tragedy and they're very upset," their lawyer David McKenzie told reporters outside court.

The charges come one day after Australian customs released a report into the tragedy which said that authorities had not spotted the boat until it was about 600 metres (yards) from Christmas Island, just an hour before it crashed.

The maximum penalty for people-smuggling offences is 20 years' imprisonment and/or fine of $220,000. The charges against the three men do not relate to any of the deaths.