REMBANG (Indonesia), Dec 30: More than 500 people were missing on Saturday after an Indonesian ferry sank in a storm off the coast of Java, where search and rescue efforts were being hampered by rough seas.

Officials said they lost contact with the vessel around midnight when it was off the Java coast.

At least 59 people had been rescued and a life raft had been found with an unknown number of people in it, port official Slamet Rahardjo told reporters in Semarang, the original destination of the ferry.

Twenty-one survivors found in a life raft were late Saturday brought into Rembang port on the coast, 100 kilometres northeast of Semarang.

Looking very tired after their ordeal, they disembarked from a tugboat in front of a crowd of onlookers before being whisked away by police to the local hospital, where 19 earlier survivors had also been taken for checkups.

The ferry was carrying 545 passengers and 57 crew when it sank, Rahardjo said. It was licensed to carry 850.

Heavy seas with waves five to six metres high were hampering search and rescue efforts with only larger navy ships able to go out, as two other ships were forced to turn back.

“The search will continue tonight with two naval ships,” Transport Minister Hatta Radjasa told MetroTV after arriving in Semarang, where anxious relatives searched lists of survivors for news of loved ones.

Radjasa said “we are using our maximum efforts to rescue as many people as possible”.

He later told ElShinta radio the ship was built in 1990 and serviced earlier this year, “so it should not have had any problems”.

“The huge waves had caused the ship to sink,” he said.

The “Senopati Nusantara” (Archipelago Commander) had been due in Semarang late Friday after what should have been a 19-hour voyage.

Navy ships and helicopters earlier found some of the survivors stranded on the nearby island of Bawean, but could not find any trace of the ship, ElShinta radio said.

One survivor said 19 people were plucked from the sea by passing fishermen and taken to Bawean.

He described panic as the ship rocked violently before sinking late at night.

“Finally, at about 11:00 pm, people were really panicking as we could feel the ship rocking violently. People were then asked to put on their life jackets and hang on to some floats,” Holit told ElShinta.

“We were all suddenly thrown into the water and floating on the sea, and I had lost my daughter,” he said.

“I hung on to a float and at 6:00 am the next day a fisherman's boat spotted us after hearing our cries for help,” said Holit, whose 18-year-old daughter, Lailatul Badriah, was still missing.

The ferry left Kumai in Central Kalimantan province on Borneo island en route to Semarang in Central Java 420 kilometres away, and sank near Mandalika island off the Java coast. It was not known exactly where it went down.

Radjasa, the transport minister, said earlier port officials should not have allowed the ferry to sail in bad weather conditions.

“At this moment the waves are over four metres high and the weather is unpredictable.

“I am calling on the (port) administrator to take heed of the instruction given out by the transport department to consider the weather conditions first whenever ships request permission to sail,” Radjasa was quoted as saying by the official Antara news agency.

“When the weather is impossible, do not give permission to those ships,”said Radjasa.

The local weather office said the seas north of Java would not be safe for navigation for the next two or three days due to tropical storms, Antara reported.—AFP