Indonesian rescuers today used drones and sniffer dogs to search for survivors along the devastated west coast of Java hit by a tsunami that killed at least 429 people, warning more victims are expected to be uncovered as the search expands.

Thick ash clouds continued to spew from Anak Krakatau, a volcanic island where a crater collapse at high tide on Saturday sent waves smashing into coastal areas on both sides of the Sunda Strait between the islands of Sumatra and Java.

At least 154 people remain missing. More than 1,400 people were injured, and thousands of residents had to move to higher ground, with a high-tide warning extended to Wednesday.

Rescuers used heavy machinery, sniffer dogs, and special cameras to detect and dig bodies out of mud and wreckage along a 100-km (60-mile) stretch of Java's west coast and officials said the search area would be expanded further south.

"There are several locations that we previously thought were not affected," said Yusuf Latif, spokesman for the national search and rescue agency.

"But now we are reaching more remote areas...and in fact there are many victims there," he added.

The vast archipelago, which sits on the Pacific "Ring of Fire", has suffered its worst annual death toll from disasters in more than a decade.

Earthquakes flattened parts of the island of Lombok in July and August, and a double quake-and-tsunami killed more than 2,000 people on a remote part of Sulawesi island in September.

It took just 24 minutes after the landslide for waves to hit land, and there was no early warning for those living on the coast.

TEMPORARY SHELTERS

Authorities have warned of further high waves and advised residents to stay away from the shoreline.

"Since Anak Krakatau has been actively erupting for the past several months additional tsunamis cannot be excluded," said Dr Prof Hermann Fritz, from the Georgia Institute of Technology in the United States.

Rescue efforts were hampered by heavy rainfall and low visibility. Military and volunteer teams used drones to assess the extent of the damage along the coast.

Food, water, blankets, and medical aid is trickling into remote areas via inland roads that are choked with traffic.

Thousands of people are staying in tents and temporary shelters like mosques or schools, with dozens sleeping on the floor and using public facilities. Many remained traumatised by the disaster.

"We can't sleep at night, and if we get to sleep a car goes past with sirens and we wake up again, on edge," said Enah, a 29-year-old woman who managed to survive with her family.

A local official in the city of Labuan, Atmadja Suhara, said he was helping to care for 4,000 refugees, many of whom had been left homeless.

"Everybody is still in a state of panic," he said. "We often have disasters, but not as bad as this."

"God willing," he said, "we will rebuild."

Destruction was visible along much of the coastline where waves of up to 2 metres (6 feet) crushed vehicles, felled trees, lifted chunks of metal,, wooden beams and household items and deposited them on roads and rice fields.

Out in the strait, Anak Krakatau (Child of Krakatau) was still erupting and authorities imposed a 2-km exclusion zone around it

The meteorology agency said that an area of about 64 hectares (222 acres), or about 90 soccer pitches, of the volcanic island had collapsed into the sea.

In 1883, the volcano, then known as Krakatoa, erupted in one of the biggest blasts in recorded history, killing more than 36,000 people in a series of tsunamis, and lowering the global surface temperature by 1 degree Celsius with its ash. Anak Krakatau is the island that emerged from the area in 1927, and has been growing ever since.

President Joko Widodo, who is running for re-election in April, told disaster agencies to install early warning systems, but experts said that, unlike tsunami caused by earthquakes, little could have been done in time to alert people that waves were coming.

The timing of the disaster over the Christmas season evoked memories of the Indian Ocean tsunami triggered by an earthquake on December 26, 2004, which killed 226,000 people in 14 countries, including more than 120,000 in Indonesia.