In a harrowing reminder of the 2004 disaster that left 220,000 dead across Asia, walls of water up to three metres (10 feet) high smashed ashore Monday, toppling buildings and sending thousands of terrified residents fleeing.

 The tsunami was triggered by a 7.7-magnitude undersea earthquake off the south coast of Java island, where no early warning system had yet been put in place and many residents had no inkling of the tragedy to come.

 Heff Martin, a 26-year-old Swiss office worker, said he and his fiancee had only moments to "think with clear heads and use common sense" to save their lives.

 "There were people screaming outside the hotel, so one of the hotel staff went outside to see what was happening. He came back screaming, 'There is a wave, there is a wave. The sea is coming, the sea is coming!'" Martin recalled.

 "We quickly ran to the second floor and soon the waves came in and crashed into the first floor... We were there for about five minutes, and we went up to the rooftop by breaking through the ceiling."

 At least 304 people were killed and 430 injured across six districts along the south coast of Central and West Java provinces, the health ministry said.

 Some 150 were still missing while 52,700 had been displaced by the surges of water, the head of the ministry's crisis centre, Rustam Pakaya, told AFP.

 Most deaths were in the resort area of Pangandaran in West Java's Ciamis district, about 270 kilometres (170 miles) southeast of Jakarta, he said.

 Agus Sutrisno, head of disaster relief in Ciamis, said more than 1,500 workers were combing coastal areas looking for survivors and bodies.

 "We suspect there are still many people buried under the debris. We lack heavy equipment such as backhoes and electric chainsaws," he said.

 A 26-year-old Frenchwoman was among the dead, a diplomatic source told AFP, while Metro TV reported that six foreign nationals were among the injured, including two Dutch and four Japanese.

 Two Swedish children aged between five and 10 years old reported missing on Monday were yet to be located, another diplomatic source said.

 Resident Ade Iskandar told the Detikcom online news agency that most of the dead in Pangandaran were children and teenagers.

 "Usually every afternoon children and teenagers surf or play football at the beach," he said.

 Tsunami alerts were issued for parts of Indonesia and Australia but they did not reach the victims as no early warning system was in place.

 "Our system is not yet working properly. We are still developing a communication system especially for the regions," Fauzi, an official working on the early warning project from the meteorology agency in Jakarta, told AFP.

 He said that while two sensor buoys had been installed on Sumatra, none were expected to be ready for Java for another two years.

 A 24-year-old surfer Budi said he was offshore at Batu Keras beach, 30 kilometres west of Pangandaran, when the quake struck.

 "I couldn't feel anything and then about five minutes after the water subsided, the waves came," he told AFP.

 Budi said he thought the ocean drawing back may have been a sign of the waves about to lash the coast, but many people began rushing out towards the withdrawing waters to look at fish flapping -- an eerie reminder of the way many lives were claimed in December 2004.

 At Pangandaran, a sleepy vacation spot boasting one of Java's finest beaches that lures both domestic and foreign tourists, residents were slowly returning to inspect damaged homes.

 The beach and nearby streets were strewn with chunks of concrete, wooden planks that were once food stalls and tiles ripped from hotel roofs, while boats were marooned on shore.

 At one morgue about 30 bodies lay on the ground, some already identified and others yet to be claimed, as survivors frantically searching for loved ones streamed in.

Agence France Presse