A strong 6.5-magnitude earthquake rattled northern Australia and parts of Indonesia Wednesday with residents in Darwin reporting widespread shaking, but there were no immediate reports of damage.

The tremor struck off the coast of eastern Indonesia, U.S. seismologists said, but no tsunami warning was issued.

"TV nearly rattled off the cabinet, two storey house was swaying around," said Rosie McCurrach on broadcaster ABC's Darwin Facebook page.

Another poster said: "Mitchell Centre felt like it was going to tumble over," while Gaylene Whenmouth noted: "On 7th floor in the city. Rocking and rolling!"

The undersea quake hit about 278 kilometres (172 miles) east-northeast of Dili in East Timor at a depth of 158 kilometres, the U.S. Geological Survey said.

Australia's Northern Territory News said the quake was widely felt across Darwin and surrounding areas.

"We're on the third floor and it gave us a shake," said Darwin-based Bureau of Meteorology senior forecaster Chris Kent, who said the quake lasted several minutes.

Indonesia's disaster agency said residents in the southwest of the Moluccas island chain also felt the quake but there were no reports as yet of damage or casualties.

Indonesia experiences frequent seismic and volcanic activity due to its position on the Pacific "Ring of Fire", where tectonic plates collide.