Police say the incident happened in the Lisburn Road area of south Belfast on last night, Friday, February 17.
Investigating officer Detective Constable McShane said: “It was reported that shortly after 11pm on Friday evening, a woman was assaulted outside a restaurant by a man armed with a hammer.
“He attempted to take the woman’s handbag from her and a struggle ensued when the woman refused to hand it over.
“The woman was struck with the hammer a number of times on the arm before the man made off empty handed along nearby Lower Windsor Avenue.
“He was described as being around 5’6” tall and was wearing a grey hooded top, blue jeans and a dark coloured baseball cap.
“The woman suffered bruising to her arm and was left badly shaken following the incident.”
Anyone with any information about this incident is asked to contact detectives at Musgrave on 101 quoting reference number 1398 of 17/02/17.
Information can also be given anonymously through the independent charity Crimestoppers on 0800 555 111.