Energy and mining projects of Australian companies, including that of the Rio Tinto Group Group and Woodside Petroleum Ltd and Fortescue Metals, are threatened by two cyclones headed north of the country, according to the Bureau of Meteorology.

The government agency said Tropical Cyclone Dianne was 385 kilometres (240 miles) northwest of the Western Australian town of Exmouth and near stationary at about 11 p.m. local time. The storm is forecast to intensify from Category 2 to Category 3 by 11 p.m. today as it moves southwest. Flood warnings are in place for some Pilbara and Mid West regions.

Related reports of Bloomberg News said the storm has already slowed transport at Rio Tinto's iron ore operations in the Pilbara and halted production at Woodside's Enfield oil field.

A La Nina phenomenon has been causing the severe wet weather conditions to Australia's east and northern parts since November 2010 and is expected until April 2011.

In a report by Bloomberg, third-biggest mining company, Rio Tinto said its transport infrastructure is "slowly getting back to normal, but not there yet." Rail lines and transport are still problematic, it said.

Production in the oil fields of Woodside and Fortescue, located in the northwestern Australia had been derailed since yesterday as the rains pose problems for the staff.

The Bureau also said that another Tropical Cyclone Carlos has been downgraded to a tropical low after hitting Darwin with gale-force winds and record rainfall. At 11 a.m. local time, Carlos was over land 115 kilometres southeast of Darwin, moving at 8 kilometres an hour. It is forecast to re-intensify into a Category 1 cyclone by Feb. 19 as it heads toward the Western Australian town of Kununurra.

Darwin has recorded more than 400 millimeters (16 inches) of rain since Carlos formed, triggering flash floods, blackouts and closing the city's airport and schools, ABC News reported today.