It happened between 1.30pm and 1.50pm near a white van parked in Melbourne Street.
The injured man is 48 years old.
Police believe there were members of the public present at the time and are appealing for anyone who witnessed the altercation to call police headquarters on 631212 quoting reference number 97/1 989/23 or anonymously via Crimestoppers on 0800 555 111.