Mass grave on Tongan seabed

The Princess Ashika will be replaced by a new vessel that NZ, Australia and Japan have agreed to help pay for. Photo / Matangi Tonga Online

An independent inquiry has been ordered into the cause of last week's sinking of the Tongan ferry Princess Ashika.

Tongan Attorney General John Cauchi yesterday said the royal commission of inquiry would publish interim findings on the circumstances behind the tragedy by November 30.

The commission is likely to get help from the New Zealand Transport Accident Investigation Commission.

Sonar images of the sunken vessel were revealed yesterday.

Experts said it was possible future images of the disaster site could show the bodies of some of the 93 people believed to have drowned.

Efforts to send a Royal New Zealand Navy remote-controlled vehicle to the wreck have been called off because of bad weather, and will resume on Monday.

"In the course of that investigation, it is likely we will observe other things on and around the vessel," Lieutenant Commander Andrew McMillan said. "If there were bodies down there and they were in a near locality or on the vessel, then there is a chance that we will observe bodies."

Searchers found the sunken Princess Ashika on Wednesday in 110m of water about 20km southwest of the Ha'apai group of islands.

The wreck is too deep for New Zealand or Australian navy recovery equipment to reach.

The Tongan Government has come under fire after reports the Princess Ashika was in no condition to sail. Transport Minister Paul Karalus said the ship was seaworthy, but he has since resigned.

His ministry will be investigated by the royal commission.

Tongan Prime Minister Feleti Sevele said the commission would investigate the Princess Ashika's seaworthiness, although he noted that he had seen its certificate of seaworthiness.

Fifty-four men were rescued when the ship sank, and only two bodies have been recovered.

New Zealand, Australian and Japanese diplomats met members of the Tongan Government in Nuku'alofa yesterday to discuss a replacement for the ferry.

It is understood the three countries have agreed to help pay for the vessel and expedite its arrival.