SYDNEY- Tropical Cyclone Iggy is expected to strengthen as it moves towards Australia's northwest coast on Friday, threatening the region's rich mining fields after shutting down some offshore oil production facilities.

Iggy, a Category 1 storm, was situated around 800 km (500 miles) northwest of Exmouth at 1904 GMT and moving in a southeasterly direction, Australia's Bureau of Meteorology said on Friday.

Category 1 is the lowest of five cyclone ratings, with gale force winds gusting 90-125 km/h (56-78 m/h).

"Strong winds, heavy rainfall and abnormally large swells will be experienced near Christmas Island, the Kimberley and Pilbara coasts," the bureau said.

Companies including Rio Tinto and BHP Billiton have major iron ore mining operations in the Pilbara region.

Woodside Petroleum and Apache Corp suspended some oil production on Wednesday during to the storm system.

Tropical cyclones and temporary shutdowns are a normal part of Australian summers, but an especially stormy season can have major impacts, such as when cyclones and flooding swamped the coal-mining industry in the country's northeast a year ago.

Tropical cyclone Heidi lashed the region earlier this month, shutting the major iron ore terminal at Port Hedland.