WELLINGTON — More than 80 people were aboard a ferry that sank in the remote Pacific, officials confirmed on Wednesday, as a senior Kiribati lawmaker called for an independent inquiry into the vessel’s disappearance.

A multinational rescue operation is scouring vast swathes of ocean for survivors, but only seven people have been found alive so far and hopes are fading of locating any more.

Initial estimates of how many people were on the MV Butiraoi when it went missing ranged from 35 to more than 100, but officials said the numbers were slowly becoming clearer.

"Kiribati authorities have confirmed that about 80 passengers plus crew of likely about five were on the ferry," Rescue Coordination Centre NZ said in a statement.

The centre said four aircraft from New Zealand, Australia and the US had helped conduct sweeps in the area where the ferry went missing.

It said the search was concentrating on finding a life raft that was launched from the sinking ferry.

"The life raft is designed for 25 people but more can be squeezed in uncomfortably," it added.

Former Kiribati prime minister Ieremia Tabai, who represents the island of Nonouti from where the ferry departed on January 18, slammed the government’s handling of the disaster.

Tabai said his grief-stricken constituents on the island of 2,000 wanted to know why it took eight days to raise the alarm and how the unseaworthy vessel was allowed to sail in the first place.

"This tragedy demands an independent commission of inquiry," he told Radio New Zealand.

"We need to know why it happened and (who is) responsible."

The MV Butiraoi, 17.5-metre wooden catamaran, set off on a planned two-day voyage to Betio, the largest township of Kiribati’s capital, South Tarawa.

Local authorities said it ran aground and underwent repairs to its propeller shaft before it left Nonouti.

Tabai said the vessel was not believed to be carrying mandatory safety equipment such as an emergency locator beacon.

"The government is responsible because they did not look after the situation well, they should have ensured that particular vessel should not have sailed in the first place," he said.

He said the ferry was a free inter-island service that was carrying a large number of high-school students returning to Tarawa before the start of a new term.

Tabai said the ferry’s loss was a tragedy for Kiribati, a nation of 33 atolls and reefs with a population of about 110,000, that lies some 3,460km northeast of Fiji.

"It’s a real sad day for those who lost their loved one. For my village two or three people that I personally know, that live next door in my village, were on that boat and perished." — AFP