Jakarta  - An earthquake registering 6.1 on the Richter scale struck off the easternmost Indonesian province of West Papua Sunday morning, but there were no immediate reports of injury or damage, the Indonesian seismologist agency said.

The quake struck at 12:36 pm (0536 GMT) and was centred in the sea about 123 kilometres north-west of Manokwari on West Papua province, and occurred at about 56 kilometres beneath the seabed, Indonesia's National Meteorology and Geophysics Agency said.

There were no immediate reports of injuries or structural damage from the quake, the latest of a series earthquake to jolts Indonesia in recent days.

In West Sumatra, rescue workers intensified their search for survivors who trapped under rubble of collapsed buildings as hopes slim in findings them alive four days after a powerful quake struck the province. The official death toll from Wednesday's quake stood 548 on late Saturday, with hundreds of others remained unaccounted for.

Indonesia, the world's largest archipelago nation, sits along the Pacific Ocean's "Ring of Fire," where the meeting of continental plates causes high volcanic and seismic activity.

A major earthquake and subsequent tsunami struck in December 2004, leaving more than 170,000 people dead or missing in Indonesia's Aceh province and half a million people homeless. (dpa)