Pressure is growing on the Australian government to explain the explosion of a boat carrying suspected asylum seekers off Ashmore Reef on Thursday, April 16.

According to The Age, the Northern Territory Coroner has found that the provisional cause of death of three of the asylum seekers was drowning. Two are still missing.

"Because of the extraordinary interest in these deaths, I have determined to release the results of the autopsies on the deceased," Greg Cavanagh said in a statement. "These have found the provisional cause of death is drowning - subject to toxicology and other forensic pathology tests.”

Meanwhile, 41 survivors are being treated in hospitals in Perth, Darwin and Brisbane.

An investigation into the matter will focus on the response of personnel on two Royal Australian Navy patrol boats, ‘HMAS Albany’ and ‘HMAS Childers’, the two vessels nearest the asylum seekers’ boat at the time of explosion.