Questions are growing about a passenger ferry believed to have sunk off the coast of Vanuatu as rescuers search for more than 30 people who remain missing.

The sinking on Friday, which officials said wasn't reported for almost a full day, has killed at least two people.

No further bodies or survivors were recovered on Monday from the sea or coastline near where the MV Matui was believed to have sunk, local news outlet VBTC said.

Two bodies were recovered and 14 survivors were found by rescuers over the weekend, the broadcaster said, citing police.

Vanuatu Police Assistant Commissioner David Bongranlie gave the total number on board as 53 on Tuesday, according to VBTC.

The circumstances of the sinking, including when it happened, weren't clear.

Vanuatu police said they hadn't been told the vessel was missing until 22 hours after it was believed to have sunk, VBTC reported Bongranlie as saying.

Vanuatu's Daily Post reported that the vessel wasn't approved to carry more than 30 people and left on Friday without the knowledge of the country's Maritime Safety Authority, according to a statement from an agency spokesperson.

The news outlet also reported the company that owned the vessel was de-registered from Vanuatu's business register in June.

Tui Shipping, the boat's owner, provided a statement to VBTC expressing sympathy to those affected and acknowledging its responsibility for passenger safety, according to the broadcaster on Tuesday. The statement didn't disclose any details about the sinking.

The office of Prime Minister Jotham Napat wrote on social media Tuesday was cancelling a planned trip to the United Nations General Assembly in New York to deal with the disaster.

"A lot of valid questions are being asked publicly that demand answers and solutions," Napat said in the statement.

"The Government acknowledges that this situation could have been minimized or avoided had all responsible authorities been alert and up to the task."

On Sunday, Napat suggested in a statement that the sinking could have happened due to "negligence including overloading of the vessel," as well as marine warnings going unheeded.

The country's meteorological service issued an alert for strong winds and high seas on the day the ferry sailed.

Napat's statement referred to the episode as a "tragedy" and an "incident" but he has not used the word "sinking".

The ship is reported to have sunk by local news outlets, citing police.

On Sunday, the maritime search and rescue agency from the neighbouring island nation of New Caledonia said on Facebook that it was co-ordinating an air and sea search for bodies and survivors. The agency gave the number of people still missing as 37.

Vanuatu is an archipelago of 83 islands in the South Pacific Ocean, located about 1750km east of northern Australia.

Australian Associated Press