The barrel of what police suspect to be part of a war-era artillery cannon was found on Tuesday at a construction site in East Tsim Sha Tsui, leading to the evacuation of around 40 workers.
The police's explosive disposal squad was deployed to the site inside the Urban Council Centenary Garden after it was discovered at 12.10pm.
Out of caution, officers sealed off a section of Granville Road between Chatham Road South and Science Museum Road for more than an hour.
The force said the cannon is around four metres long.