The aftershock struck at 10:41 am (9.41AM Singapore time) and was centred 248 kilometres northwest of Saumlaki town in Maluku province, the office said in a statement.

There was no risk of a tsunami, the office said.

Indonesia sits on the Pacific 'Ring of Fire' where continental plates meet, causing frequent seismic and volcanic activity.

The archipelagic nation was hardest hit by the earthquake-triggered Asian tsunami in December 2004 which killed an estimated 168,000 people in Indonesia's Aceh province. -- AFP