Police have commenced an investigation following an armed robbery in Lake Macquarie.

Just before 9pm on Tuesday 28 November 2017, a man armed with a knife, entered a service station on Wilsons Road, Mount Hutton.

Police have been told the man threatened the store employee with the knife and demanded cash, before fleeing the scene with an amount of money.

Officers attached to Lake Macquarie Local Area Command established a crime scene and commenced an investigation.

They would like to speak to a man who might be able to assist with their inquiries.

He is described as being about 180-185cm tall, with olive skin and of a thin build. He was last seen wearing a blue beanie with white writing, a white bandana across his face, black leather jacket and dark pants.

Inquiries are continuing and anyone with information is urged to contact police.