A magnitude 6.7 earthquake rocked the coast of Australia's remote Macquarie Island today, the US Geological Survey said.

The quake struck west of Macquarie Island at 2.54pm local time (4.54am Irish time), and was centred six miles below the seabed. The US Geological Survey originally recorded the quake as a 6.3 magnitude, but later upgraded the quake to 6.7.

Stuart Koyanagi, a geophysicist at the Pacific Tsunami Warning Centre at Ewa Beach, Hawaii, said the quake was unlikely to generate a major Pacific-wide tsunami.

"Normally at this magnitude we don't expect any kind of destructive tsunami," he said.

Clive Collins, a seismologist at Geoscience Australia, said the Macquarie Island earthquake involved two tectonic plates moving against each other horizontally, rather than vertically, and was unlikely to displace the large quantity of water needed to generate a tsunami.

"It's most unlikely there would be any tsunami," he said. "It's a fairly large earthquake and it's fairly shallow, but we don't think there's any risk."

The isolated, sparsely populated island lies about 835 miles south of the island state of Tasmania, and serves as a base for Australian expeditions to Antarctica.