Thousands of people have held a memorial in Indonesia's Aceh province, the epicentre of the Indian Ocean tsunami, as the world prepares to mark a decade since a disaster that took 220,000 lives and laid waste to coasts in 14 countries.

On December 26, 2004 a 9.3-magnitude earthquake off Indonesia's western coast sparked a series of towering waves that wrought destruction across countries as far apart as Indonesia, Thailand, Sri Lanka and Somalia.

Among the victims were thousands of foreign holidaymakers enjoying Christmas on the region's sun-kissed beaches, striking tragedy into homes around the world.

Muslim clerics, tsunami survivors and rescue workers led around 7000 mourners gathered at Banda Aceh's black-domed Baiturrahman Grand Mosque for memorial prayers late on Thursday.

Aceh governor Zaini Abdullah thanked Indonesians and the international community in his address at the mosque, one of the few buildings which withstood the wrath of the massive earthquake and ensuing waves which left 170,000 people in the country dead or missing.

"The tsunami had caused deep sorrow to Aceh residents from having lost their loved ones," he said.

"Sympathy from Indonesians and the international community has helped (Aceh) to recover," he added.

He also called on residents not to "dwell in our grief, so that we could rise from adversity and achieve a better Aceh".

In Meulaboh, a fishing town considered to be the ground zero of the tsunami -- where 35 metre-high waves flattened almost everything -- Indonesian flags were flown at half-mast as small groups of residents held night prayers at mosques.

The main memorials were planned for Friday morning, starting in Aceh which was hit first by the waves, then moving to Thailand where candlelit ceremonies are expected in the resort hubs of Phuket and Khao Lak.

Many of the tsunami's victims died in dark, churning waters laden with uprooted trees, boats, cars and eviscerated beach bungalows, as the waves surged miles inland and then retreated, sucking many more into the sea.

The world poured money and expertise into the relief and reconstruction, with more than $US13.5 billion collected in the months after the disaster.

Almost $US7 billion in aid went into rebuilding more than 140,000 houses across Aceh, thousands of kilometres of roads, and new schools and hospitals.

The vast majority of Indonesia's 170,000 victims perished in the province, among them tens of thousands of children.

But the disaster also ended a decades-long separatist conflict, with a peace deal between rebels and Jakarta struck less than a year later.

It also prompted the establishment of a pan-ocean tsunami warning system, made up of sea gauges and buoys, while individual countries have invested heavily in disaster preparedness.