Police are investigating an aggravated robbery in the CBD this morning.

Just after 5am on Sunday 13 January, three men armed with a sledge hammer and an axe entered a licensed premises in Pulteney Street and threatened staff before stealing an amount of cash.

The trio were last seen getting into a waiting silver Holden sedan being driven by a fourth man. The car drove off heading south on Pulteney Street.

No one was physically injured during the incident.

One suspect is described as 180cm tall, heavy build, about 130kg and dark complexion. He was wearing black pants, a dark grey hooded top and black sneakers.

A second suspect is described as 177cm tall, about 80kg with dark complexion. He was wearing a light grey hooded top, black pants and white shoes.

A third suspect is described as 172cm tall, about 80kg with dark complexion. He was wearing black pants and a black hooded top.

All three suspects had their faces covered.