Rescuers on Monday safely recovered 13 more people from a tourist boat that sank in central Indonesia, but were searching for a Dutch man and an Italian woman who were still missing, an official said.
The boat sank Saturday evening on its way from Lombok island to Komodo island carrying 20 foreign tourists, four Indonesian crewmen and an Indonesian guide.
Ten people - all foreigners - were rescued Sunday. They included New Zealanders Tony Lawton and Gaylene Wilkinson.
Lawton and Wilkinson and another eight foreigners spent 10 hours clinging to their upturned boat off Indonesia before being rescued.
Lalu Wahyu Efendi, operational chief for the search and rescue agency in Mataram, the provincial capital of West Nusatenggara, says eight more foreigners and all five Indonesians were found early Monday.
He said the 13 were rescued by fishermen about 43 kilometeres east of where their wooden boat sank off Sangeang Api, a volcanic island in Bima district off the eastern coast of Sumabwa island.
Most of those who were rescued had minor injuries, said Efendi, adding that rescuers were still scouring the waters for the two missing foreigners.
The survivors were being treated at a clinic on West Nusa Tenggara island, which lies between Lombok and Komodo.
Conditions had turned against rescuers searching for the remaining two tourists.
"We have deployed speed boats and a helicopter ... but we are encountering bad weather and high waves," a spokesman for the agency said.
A woman who was rescued Sunday told MetroTV that she and the others swam for hours before being found.
''It was a terrible experience. We swam in choppy waters for seven hours before being found by a fisherman,'' said the woman, identified only as Maria.
The rescued foreigners included five Dutch, four Germans, three Italians, two each from Spain and New Zealand, and one each from France and Britain, said Sutopo Purwo Nugroho, the spokesman for Indonesia's disaster management agency.
The agency says the boat was hit by a 3-metre-high (10-foot-high) wave and crashed into a reef, causing it to leak and sink.
It turned upside down and sank at about 7pm on Saturday.
Some passengers clung to its side and others clambered onto the boat.
Efendi said the passengers were scattered by the tide but after about 10 hours in the water, another tourist boat, Mermaid 1, managed to pick up five tourists and five more were rescued by fishermen.
It was believed the 15 who were still missing might be drifting in an unpowered lifeboat or vessel of some kind. Thirteen were rescued on Monday.
French survivor Bertrand Homassel told the Daily Mail that he and other survivors swam for six hours to shore after the boat sank.
''People started to panic... Everyone took the decision to swim to the closest island, five kilometres away, where there was an erupting volcano.''
They arrived at the island Sangeang at sunset.
They spent Saturday night on the island, drinking their own urine and eating leaves to survive before getting rescued by a passing boat yesterday.
According to international media reports, Tajudin Sam, who ran the tour company operating the boat, said it likely encountered stormy weather. A boat ride from Lombok to Komodo can take three days.
Komodo is famous for its monitor lizards, which draw many tourists.
-AP and Fairfax NZ