A strong earthquake with a 6.4 magnitude struck southwest of Australia's Macquarie Island early today, the US Geological Survey said. The epicentre of the quake, which hit at 12:31am (AEDT), was 745 kilometres southwest of the remote Australian territory, which lies about 1,450 kilometres southeast of the island state of Tasmania. The US agency reported that the quake hit at a depth of 10 kilometres. There were no immediate reports of damage and the Pacific Tsunami Warning Centre had not issued a tsunami warning.