A powerful magnitude-6.4 earthquake has struck Lombok, killing seventeen people and injuring a dozen, the country's disaster mitigation agency says.

The quake damaged dozens of single-storey houses and taller buildings and was felt in a wider area, including in Bali, where no damage or casualties were reported.

It hit the northern part of Lombok island early on Sunday morning when many people were still sleeping.

"We jumped out of our beds to avoid anything falling on our heads," said Jean-Paul Volckaert, who was woken by the quake while sleeping in the Puncak Hotel near Senggigi on Lombok.

"I've been walking around but so far there is no damage. We were very surprised as the water in the pools was swaying like a wild sea. There were waves in the pools but only for 20 to 30 seconds," he said via telephone.

"The people in the villages may have damages. It's still early morning here."

The quake, which was quickly followed by an aftershock of magnitude-5.4 in the same area, was centred 50 kilometres north-east of the city of Mataram, the US Geological Survey said.

Sutopo Purwo Nugroho, the disaster mitigation agency spokesman, tweeted pictures of houses with collapsed roofs and walls.

The quake may have also affected Mount Rinjani national park, a popular trekking destination.

"Rinjani mountain climbing is closed temporarily because there are indication of landslide around the mountain," Mr Nugroho said in a statement.

Local news Metro TV reported that people were still sleeping when the first quake hit and they quickly fled their houses in panic. Most of the people were still waiting outside their houses in fear of aftershocks, Metro TV said.

Shallow depth amplified effect

The earthquake struck at 6:47am on Sunday (local time) and was only 7 kilometres deep, a shallow depth that would have amplified its effect. The second struck less than a hour later.

A magnitude 6.4-earthquake is considered strong and is capable of causing severe damage.

The European-Mediterranean Seismological Centre, the European quake agency, put the magnitude at 6.5.

The earthquake was on land and did not trigger any waves or tsunami.

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