WA low may become cyclone by Friday

A tropical low off the West Australian coast could form into the first tropical cyclone in the Australian cyclone season, the Bureau of Meteorology says.

The low is about 750km north of Port Hedland and is heading south at 9km/h.

The Bureau of Meteorology says that at this stage, the system is likely to intensify to category one, the weakest level on the five-level Australia cyclone intensity scale.

"The low may develop into a tropical cyclone on Friday as it tracks towards the south and approaches the Pilbara coast, the Bureau of Meteorology's tropical low advisory says.

"It is not expected to cause gales in coastal areas on Wednesday or Thursday but gales may develop on Friday."

The low's anticipated track suggests it could cross the coast somewhere between Onslow and Wallal early Saturday morning.

Gales may develop on Friday between Mardie and Cape Leveque, the BOM says.