More than 1500 people have attended Tonga's largest church service in the wake of Wednesday's ferry disaster north of the capital.
The Princess Ashika sank at about 11pm on Wednesday, with the latest estimates pointing to 93 people still missing.
There were 54 survivors and only two bodies have been found so far.
Church services took place as usual across Nuku'alofa, but on Sunday it was a special service of national prayer.
In a rare move, church leaders from the country's many denominations joined to attend the service.
It was also attended by the royal family, government ministers, and personnel from the Australian and New Zealand defence forces.
The Princess Ashika is thought to be in about 36 metres of water, about 86km north-east of the Tongan capital. It was en route from Nuku'alofa to the Nomuka Islands group.
Debris is spread over a vast area.
Tonga police commander Chris Kelley says the cause of the sinking is still unknown and warns the ferry may never be found.
Divers from the Royal New Zealand and Australian Navies arrived on Saturday to try to locate the wreck.
Lieutenant Commander Andrew McMillan says the divers are dealing with difficult and challenging conditions.
He says the navy's equipment can only work down to about 100-metres.
But he says preliminary work on Saturday shows very difficult volcanic terrain with depths of 30-metres quickly dropping to 110-metres or more.
He says a Tongan craft has shown something may be on the sea floor which is a priority to investigate, but it could be coral or something else.
Dozens of relatives of the missing are camping outside the shipping company's headquarters waiting for information.
Staff at the Shipping Corporation of Polynesia are staying at the building in shifts so relatives can be on the grounds. A makeshift tent has been set up.
The Ministry of Transport is preparing the terms of reference for an inquiry.