BANDA ACEH - Indonesia told aid workers helping tsunami victims in its worst-hit region Aceh on Tuesday not to venture beyond two large cities on Sumatra island because of possible attack by militants.

Indonesia's head of relief operations said agencies would need permission to work outside the provincial capital Banda Aceh and the ravaged west coast town of Meulaboh.

Asked if Aceh -- where the Indonesian army and separatist rebels have clashed for decades -- was unsafe for international aid workers, Budi Atmaji said: "Yes, in some places."

Indonesian military chief General Endriartono Sutarto said in Banda Aceh he had tried to contact the GAM (Free Aceh Movement) rebels about a full ceasefire, "but I got no response up to now".

But the rebels said they would never attack aid workers -- who in turn said they were not overly worried.

"In no way has it impacted or diminished our goal to move about or to access populations," said senior UN relief official Kevin Kennedy.

Huge waves triggered on December 26 by an earthquake about 150km out at sea from Meulaboh killed at least 157,000 people around the Indian Ocean -- 105,500 in Indonesia, 30,000 in Sri Lanka and 15,000 in India.

Many of the more than 5000 killed in Thailand were tourists from Europe and round the world.

Interpol and 20 national police forces launched history's biggest disaster victim identification system to unravel the mesh of forensic data from bodies, hundreds of which were to be exhumed for checks after hasty burials right after the tsunami.

Experts at the makeshift police headquarters on the tsunami-hit island of Phuket said putting names to all the corpses -- cross-referencing dental records, fingerprints and DNA from bodies and from the missing -- could take months.

Interpol said it would also help identification efforts in other countries, but along the coast of Sri Lanka, Indonesia and elsewhere, thousands of victims lie buried in unmarked graves.

Sri Lanka said it was renewing efforts to enforce a law barring people from building within 300m of the sea. Thousands of those killed by the tsunami were living in illegally constructed homes along the coast.

On India's remote Andaman islands, the sea again washed into the heart of the main city Port Blair at high tide, lapping at doors. People fled to nearby hillocks and many slept on the pavements on high ground. The water later receded.

The United Nations said international donors had acted with record speed to meet a near US$1 billion ($1.44 billion) appeal for immediate aid, with more than 70 per cent already raised.

"This has never happened before," UN emergency relief coordinator Jan Egeland said after more than 80 states met in Geneva to discuss the UN call, as well as longer term assistance to affected areas round the Indian Ocean.