Six people has died and 97 have been rescued from a stricken Indonesian passenger ferry in the Java Sea, Indonesia's search and rescue agency has said.

A search and rescue operation was launched after contact was lost with the Virgo Transport 8 ship, which was carrying 243 people, as it encountered bad weather, Indonesia's search and rescue agency said.

The search for the remaining passengers is ongoing.

The ferry was travelling from Surabaya to the South Kalimantan city of Banjarmasin and was last reported to be about 150km (93 miles) south of Banjarmasin around 02:00 local time on Sunday (18:00 GMT on Saturday).

Authorities received the initial distress report at 04:10 from the vessel's operator PT Virgo. The ship left Surabaya at 10:33 on Saturday and was scheduled to arrive in Banjarmasin on Sunday at 14:00, according to data from two maritime monitoring sites.

A joint task force involving Indonesia's search and rescue agency, navy, maritime police and other parties has been set up for the rescue effort.

Ships and a helicopter have been deployed to the scene and all other vessels in that area of the Java Sea have been alerted to report signs of any passengers.

An operations post for handling the accident was set up in the Trisakti Port area on Sunday morning.

Rusmilawati, a resident of Banjarmasin, went to the port to seek information about eight relatives who were passengers on the ship. They were travelling back to Banjarmasin after visiting the tombs of several Islamic scholars in Java.

"They flew there initially, but for the return journey they wanted to try travelling by ship," she told BBC Indonesia.

As of Sunday afternoon local time, Rusmilawati said she had not received any information from officials about whether her relatives had been rescued.

The family last heard from one of the relatives through a WhatsApp status update. In the post, the relative wrote: "The waves are really frightening tonight. Or is this just what it's normally like travelling by ship, rocking and crashing against the waves?"

"Hopefully they're safe," Rusmilawati said.

Meanwhile, Misnah broke down in tears after learning that her husband, Ahmad Supandi, had survived.

Ahmad, a freight driver, had been aboard Virgo Transport 8 and was later rescued by the vessel MV Haida.

At Tanjung Perak Port in Surabaya, relatives of crew members have also been seeking information about their loved ones.

One relative, Fredy, said his youngest sibling, Stevie Manuhua, worked aboard the vessel as a keyboard player, entertaining passengers.

"We spoke two days ago when the ship was docked in Surabaya. After that, there was no news until now," Fredy said.

He said he had still not received any information about his sibling's whereabouts.

The incident comes after a separate ferry in Indonesia caught fire off Madura island last month, killing five.

The Indonesian archipelago has more than 17,000 islands and ferries are a common form of transport.