SYDNEY, Jan 18 (Reuters) - Western Australia's iron ore hub of Port Hedland was shut due to a developing tropical cyclone off the state's vast Pilbara region, Bloomberg News reported on Saturday.

Operator Pilbara Ports Authority said all bulk carriers were to leave the port by 6 p.m. local time due to forecasts that tropical lows offshore would combine into a cyclone, Bloomberg reported.

Only essential workers would remain at the site, located about 1,301 km (808 miles) north of state capital Perth, it added.

Pilbara Ports Authority did not immediately respond to a Reuters request to confirm the report.

Australia's weather forecaster issued on Saturday a warning for gale-force winds along the coast of the Pilbara, an area twice the size of the United Kingdom, as a tropical cyclone developed.

"The developing low is expected to move west, parallel to the Pilbara coast today and on Sunday. From Monday, the cyclone is expected to be moving southwest and away from the WA (Western Australia) coast," the forecaster said in the alert.

Port Hedland is the world's biggest export point for iron ore and is used by miners including BHP Group (BHP.AX) Fortescue (FMG.AX) and billionaire Gina Rinehart's Hancock Prospecting.

(Reporting by Sam McKeith in Sydney; Editing by Kim Coghill)

((Samuel.McKeith@thomsonreuters.com;))