5.5 magnitude earthquake strikes Western Australia

The equal-largest earthquake recorded in Australia has hit off the Kimberley coast, shaking items off shelves and stunning local residents who had never felt a tremor before.

The 6.6 magnitude undersea quake struck at 3.39pm AEST on Sunday between Port Hedland and Broome, GeoScience Australia reported.

"As it stands for as long as today, it is the biggest-equal earthquake in Australia ever recorded,” the GeoScience Australia duty seismologist Dan Connolly said.

It equalled the magnitude of an earthquake recorded in Tennant Creek, Northern Territory in 1988.

The government agency first reported it at 5.5 magnitude before boosting it up. The United States Geological Survey said the quake hit at a depth of 33km, about 203km offshore. It reported the magnitude at 6.9.

"An earthquake of this size ... the enormous size, it was felt up to Darwin and down to Perth. It is a rare occurrence,” Connolly said.

There is no threat of a tsunami to the Australian mainland, islands or territories, the weather bureau said.

There have been at least four aftershocks following the earthquake, ranging from 3.8 to 5.2 magnitude, the agency reported.

Connolly said more aftershocks were expected to flow and that was "absolutely normal”, but he could not predict where, when and what size they would be.