A severe category 3 cyclone blew into the key mining region of Pilbara in Western Australia Sunday, forcing evacuations and a halt to port operations, as the north of the country dealt with the effects of an even more powerful storm that hit the previous day.

Cyclone Veronica weakened from a category 4 storm before its core winds hit the coast near the mining centre of Port Hedland, but officials warned the system was slow moving and would continue pounding the region with gale force winds and heavy rain for 24 to 48 hours.

The Bureau of Meteorology said Veronica's forward movement had stalled around midday Sunday before its eye made landfall, and was forecast to weaken to a category 1 storm overnight and then veer west along the coastline.

It said the "severe" storm was producing wind gusts of up to 200 kilometres per hour, pushing a storm surge of up to two metres onto the coast.

Rainfall was expected to hit 20-40 centimetres, it said.

"Tides are likely to rise significantly above the normal high tide mark with damaging waves and very dangerous coastal inundation," the bureau said.

Major mining and energy companies took precautionary steps across the region, a hub of liquefied natural gas and iron-ore exports, with ports cleared of ships and non-essential staff evacuated, according to australianminining.com.au website.

Australia's western coast usually sees three or four cyclones per year and emergency services said residents were well prepared for this storm.

Meanwhile, Cyclone Trevor, which hit northern Australia on Saturday as a powerful category 4, weakened to a tropical storm overnight as it moved inland in the sparsely populated region.

Officials said no deaths, injuries or significant damage had been reported from the storm, but that heavy rains were continuing and flooding was still a danger.

The army and police had evacuated more than 2,000 residents from outposts in Trevor's path, many of them indigenous communities, and people began returning to their homes on Sunday, police said.

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