An earthquake that lasted for three minutes forced Australians living in Darwin, probably already deep in dreamland, to rouse from their sleep at 2.30am local time. The source of the earthquake? A 7.3 magnitude earthquake in the Banda Sea off Indonesia that is actually more than 600 kilometres away from Darwin.

Its epicenter, measured at 180km deep, fortunately was not strong enough to trigger damage both lives and property on nearby islands as well as to trigger a tsunami, Mark Leonard, Geoscience Australia senior seismologist, said.

Nevertheless, it had been still widely felt.

"It has been felt over several hundred kilometres of Australia's coastline," he said, noting the quake was the largest to hit the Banda Arc in seven years.

"The building started shaking and it just became worse," Angeline Prasad, duty forecaster at the Darwin weather bureau, told ABC News. "It is the worst tremor I've felt in Darwin.

"When things started falling off shelves we decided to go to an evacuation point, which is outside the building."

Another reported feeling her bed moving.

"The bed was really shaking violently, all my sliding doors rattling and windows were rattling and the wardrobe was sliding violently and rattling," an unidentified woman told ABC News. "It just seemed to go on and on and on, and then when it died down it even had another violent shudder again.

"It certainly got the adrenaline running."

An engineering specialist said this could be the most opportune time to review building standards in northern Australia.

"The big one is yet to come," Professor Kevin McKew from Central Queensland University said, "We haven't had a great earthquake, as I would call it, but we've had plenty of warning calls.'

"I think it will happen, it's just a matter of when will it happen.

Although Darwin was lucky to have only felt shakes, Professor McKew said what happened this morning is a warning that a large, damaging earthquake could strike at any time.

"We know it is probably a once in 300 or 400 year earthquake but we have no indication to say when it's about to happen.

"But we just have to plan for it."