Wellington  - Australian and New Zealand search teams said Wednesday they have located the wreck of the sunken Tongan ferry Princess Ashika on sonar, but ruled out the possibility of finding more survivors.

Tongan police commander Chris Kelly said the dive teams found the boat at 11 am Tongan time (2200GMT) on sonar, 11 nautical miles south south-west of Nomuka in Ha'apai.

"It fits the general size and shape of the missing ship," Kelly said.

His comments were reported by Radio New Zealand and confirmed to the German Press Agency dpa by Tongan police.

"It appears to be intact, in an upright position at a depth of 110 metres," Kelly said.

"It is important to realize that nobody on board could still be alive," he added.

The Tongan ferry sank a week ago with at least 149 people aboard. Authorities estimate that 93 bodies remain trapped in the vessel since it sunk last Wednesday evening.

Kelly said the team had not visually confirmed the identity of the vessel but "we have a high level of confidence it is the Princess Ashika."

A New Zealand dive tender will arrive in Nuku'alofa on Saturday with a deep diving remote-operated vehicle.

"This underwater vehicle will provide images that will give 100 per cent certainty to the identity of the vessel," Kelly said.

The police have suspended operations for the next two days because of bad weather.

Authorities estimate that 93 bodies remain trapped in the vessel since it sunk last Wednesday evening around midnight (around midday GMT).

Tong police operation head Sokopeti K To'ia issued a statement Monday morning which confirmed that the known survivors are 54 Tongan males, aged between 10 and 70 years old.

Tonga's Transport Minister Paul Karalus resigned Tuesday evening. He told Radio New Zealand that he did not want to appear to prejudice any investigation into the incident.

Karalus refused to accept any responsibility for the sinking. He told the radio station that "the vessel was seaworthy at the time the survey was undertaken."

His resignation follows the ferry captain's claims to Tongan media that the government knew the vessel was not seaworthy, and ignored his requests for repairs.

Long-serving Tongan politician and People's Representative party member Akilisi Pohiva told dpa that the sinking of the ferry was "manslaughter by negligence."

Pohiva said he was one of many people who had warned the government that the Princess Ishika was not safe.

Police commander Kelly told dpa that authorities were still trying to establish the identity and number of passengers on board.

He told a press conference in Tonga on Tuesday that two foreign nationals believed to be passengers had contacted authorities and said they were not on the ship.

Kelly identified the second body that police had recovered. She was a 22-year-old wife and mother named Vaefetu'u Mahe. Her husband and child are among the 93 who remain unaccounted for.

Kelly said he hoped to release a provisional list of passengers later on Wednesday.

Authorities had previously said the ship carried one Japanese crew member, two French and two German passengers. The body of a British national, Dan MacMillan, has been recovered.

Authorities suspect a wave hit the vessel and threw several vehicles and containers held in cargo to one side of the boat, causing it to capsize.

Water quickly poured through the low windows of the ferry, causing it to sink rapidly. (dpa)