A knife-wielding man threatened a staff member at Sorrento BP in the early hours on Monday.

WA Police spokeswoman Barbara Crane said the man, wearing black pants and a black hooded jumper, entered the West Coast Drive petrol station about 3am.

He threatened the attendant with the knife, demanded money and fled with the cash.

He was described as fair-skinned and about 180-185 centimetres tall.

Anyone who can assist in this investigation is asked to call Crime Stoppers on 1800 333 000 FREE.

Extracted in full from WA Today.