HONG KONG • Bomb disposal officers in Hong Kong yesterday successfully defused a 450kg wartime bomb discovered at a construction site in Wan Chai.

A construction worker made a report to police at 7.40am on Saturday, prompting the evacuation of 1,300 people.

Several roads around the Hong Kong Convention and Exhibition Centre were closed from midnight on Saturday. Ferry services were also suspended and at least half a dozen cross-harbour and island bus routes were affected during the bomb disposal operation, reported the South China Morning Post.

At about 11am yesterday, officers initiated the process of burning off the explosive material inside the device. A plume of smoke was seen coming from the worksite.

The operation ended at 1pm, senior bomb disposal officer Chow Shek Kin with the Explosive Ordinance Disposal Bureau told reporters at the site yesterday. He said the operation took longer than usual due to the size of the bomb.

Officers said the ANM-65 device, containing about 225kg of explosives, was dropped from the air by American bombers between 1941 and 1945. The large cylindrical device, measuring 140cm long and 45cm in diameter, was unearthed 15m down in the soil.

The police had to defuse the bomb on site because moving it would have posed a danger. "If the bomb explodes, the force could affect the surrounding area within 200m, with fragments flying as far as 2,000m," Mr Chow said.

Those evacuated included residents and workers from nearby offices and hotels, and the convention centre, reported local media.

In January last year, a 220kg unexploded US wartime bomb was found at a construction site in Pok Fu Lam. The airdropped bomb - model AN-64 - contained about 120kg of TNT explosives.