Machete used in west Sydney hold-up

A thief has threatened a man with a machete during a hold-up of a petrol station in Sydney's inner west.

The armed robber entered the service station on Unwins Bridge Road at Sydenham and threatened the attendant with the weapon about 1.30am (AEDT) on Thursday, police said in a statement.

The thief then fled the premises with a large amount of cash and was last seen on Unwins Bridge Road.

He is described as being of Middle Eastern or Mediterranean appearance, in his late teens or early 20s, with a chubby build and black hair.