A shop assistant has been punched in the head after he confronted a shoplifter over a pair of Nikes.

The incident happened after a man entered a sporting footwear store in Westfield Innaloo Shopping Centre at 11am on Thursday.

The man took a pair of Nike sneakers off the shelf while walking out of the store when a 28-year-old staff member tried to stop him.

The offender punched the staff member in the head, dropped the sneakers and fled the store.

The offender is described as having a fair complexion with tanned skin, approximately 180 centimetres tall with a muscular build and light brown short hair.

He was wearing jeans, black T-shirt with red print and black shoes.

Anyone with any information is asked to call Crime Stoppers on 1800 333 000.