It happened in the Friendly Street area of Market district in south Belfast on Sunday, December 4.
Police say that around 3 pm officers received a report that a man aged in his 20s was assaulted by a number of men thought to be armed with hammers.
He was taken to hospital for treatment to his injuries which are not believed to be life threatening.
Detective Sergeant McPhillips has appealed to anyone who may have witnessed this incident to contact Detectives at Reactive and Organised Crime at Musgrave on the non-emergency number 101, quoting reference 773 04/12/16.
Alternatively, if someone would prefer to provide information without giving their details they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.