At least 500 people are feared to have drowned after a ferry travelling between the Indonesian islands of Borneo and Java sank during a storm.
Distraught friends and relatives have gathered at Semarang port
Rescue efforts have been hampered by choppy seas and high winds.
About 62 people have been accounted for, reports say, with many survivors sheltering on smaller vessels or nearby islands because of the bad weather.
The ship was travelling from the port of Kumai on the island of Borneo to Semarang on the main island of Java.
A local police chief said the boat had only 200 listed passengers but most reports say the real number aboard the vessel was more than double that.
Ships and ferries are a cheap and popular means of transport between the 17,000 islands that make up Indonesia.
Correspondents say safety standards are not always enforced and vessels frequently carry more passengers then they are meant to.
The boat is thought to have sunk about 40 km (24 miles) off Mandalika island, about 300 km (190 miles) north-east of the capital, Jakarta.
According to a naval official interviewed by the BBC, the ship's crew contacted the coastguard shortly after midnight to say they had lost control of the vessel.
Rescue teams have been ready at Semarang harbour since morning but massive waves and high winds have prevented their boats from setting out, BBC correspondent Lucy Williamson reports.
A survivor interviewed by the Associated Press news agency said passengers on the boat began praying as the waves rose around them.
The survivor, who gave his name as Cholid, said passengers also fought over life jackets as the boat capsized.
"I was going upstairs to try to help my daughter, but the ship suddenly broke up and I was thrown out. I lost her," he said.