As police investigate an attempt robbery at a Murray Bridge supermarket late today, it is hoped CCTV images of the alleged offender will assist.

About 4.40pm, a Caucasian male with a brown/red beard, approximately 170-175cm and of thin build entered the IGA supermarket on Swanport Road.

He went to the counter, requested tobacco and then grabbed staff member by wrist and pulled out a large knife demanding cash.

The staff member stepped away and no money was handed over.

He left the store and was chased by staff but not located.

The offender may have had a piercing or bar at the back of the neck and was wearing a white hooded top, a beanie and baggy track pants with sneakers.

If you recognise the man or have any information that may assist police, please call Crime Stoppers on 1800 333 000 or report online at www.sa.crimestoppers.com.au