New Zealand ship HMNZ Manawanui is tonight setting up anchor in deep, rough water above a sunken ferry northeast of the Tongan capital of Nuku'alofa.
The navy ship was in water 110 metres above the MV Princess Ashika, which sank on August 6 with at least 149 people aboard.
Weather at the site was improving rapidly, with its crew expecting to deploy its submarine to investigate tomorrow.
Dive team Lieutenant Commander Andrew McMillan told Radio New Zealand the sailors would use a remote operated vehicle (ROV) to confirm the ship was in the right place by seeing the vessel's name on its side.
Sonar indicated the freshly sunken ship was surrounded by debris and he would not send the submarine into the ferry to confirm how many bodies were still trapped, Lt Cmdr McMillan said.
"If it does get entangled in any of the debris or these ropes or obstructions, then I may not get my ROV back ."
After confirming the vessel was in fact the Princess Ashika, the navy ship would assist in the ongoing search and rescue operation and help the transport investigation to establish the cause for the sinking, he said.
So far, only two bodies had been recovered, with another 93 believed to be still in the ship.
Only 54 men survived the sinking, with most of the passengers sleeping in their cabins when the ship went down.
The Matangi Tonga newspaper said on its website that groups of mourners continued to hold prayer services and vigils at Queen Salote Wharf and outside the Shipping Corporation of Polynesia Ltd. offices.
