SYDNEY, Dec 25: The world's biggest earthquake in almost four years, measuring 8.1 on the Richter scale, struck off the coast of Australia's southern island state of Tasmania early on Friday, but caused no damage or injury.

Seismological officials said it was felt throughout Tasmania and the South Island of New Zealand, but because it occurred at a depth of 10 kilometres and far from inhabited land, it was barely noticed even by the scientists or penguins on nearby Macquarie Islands.

Geoscience Australia said the epicentre of the quake, which struck at 1459 GMT, was 400 kilometres off Macquarie Island and 800 kilometres off the coast of Tasmania, halfway between Australia and Antarctica.

Seismologist Cvetan Sinadinovski said it caused buildings to shake in the island state for up to 15 seconds, but did not cause a tsunami or unusual tidal activity because it was of horizontal rather than vertical displacement and struck far off the coast.

"If it happened underneath a population centre in Australia, this would probably have destroyed a whole city," Sinadinovski said.-AFP