JAKARTA - INDONESIA scaled down the search on Tuesday for around 230 people still missing two days after a ferry capsized in heavy seas off Sulawesi, as investigators began probing the cause of the disaster.

High winds and rough seas continued to pound the Makassar Strait between Sulawesi and Borneo islands where the 700-tonne Teratai Prima capsized and sank with some 267 people on board early on Sunday.

Smaller vessels were ordered to give up the search and only four navy warships and two patrol boats continued to look for survivors in the treacherous strait, known for strong currents and unpredictable seas.

'We are facing very bad weather and rough seas. We don't want to take any risks by sending small boats,' transport ministry maritime official Sunaryo said said.

He said 34 people had been rescued since the alert was raised late Sunday and only one body had been found, leaving 232 people missing feared dead.

'We found more than 15 people during yesterday's search, including a dead woman whose body was floating in the sea,' he said.

Senior officials have said there is little hope any of the missing passengers and crew will be found alive more than 48 hours after the ferry was hit by a powerful monsoonal storm 50 kilometres off Sulawesi.

The ferry, operated by private company PT Nur Budi and built in 1999, was sailing from Pare-Pare in South Sulawesi bound for Samarinda, Borneo island when it went down.

An investigation is underway amid claims that the vessel was overloaded, inadequately equipped with lifeboats and ignored storm warnings. Australian transport experts would help with the probe, officials said.

Survivors said most passengers were asleep when the ferry suddenly listed to the left and capsized in huge waves whipped up by the tropical storm.

Some were picked up by fishermen after about seven hours adrift. Two told AFP they had clung to bunches of bananas to stay afloat.

Relatives of the missing passengers crowded search command posts on Sulawesi overnight, hoping for news of their lost loved ones.

Ms Sumaena, a teacher from Sulawesi, said five members of her family were missing.

'We will continue waiting. Hopefully our family members have been found alive like those who arrived earlier,' she was quoted as saying by the Antara news agency at the search post in Pare-Pare.

Another woman, Rumaedah, wept as she waited for news.

'We heard that 21 passengers were found stranded on Ambo Island. We hope they are our relatives,' she said.

Indonesians rely on ferries to connect the main islands of the massive archipelago, but accidents are common and safety regulations are badly enforced.

This week's disaster is the worst of its kind in Indonesia since December 2006 when a ferry sank in a storm off the coast of Java, killing more than 500 people.

Transport ministry senior official Sunaryo said investigators would look at why the captain, who survived, had ignored storm warnings when he set sail on Saturday afternoon.

Officials have said the weather was fair as the ferry departed Pare-Pare.

'We are questioning the ferry captain and port administrators who issued a permit for the ferry to sail amid a series of warnings from the meteorology office over the bad weather,' Mr Sunaryo said.

'We will investigate which party is responsible in this case, and if anything is proven we will bring them to justice.' -- AFP