Hong Kong police have sealed off part of a busy downtown neighbourhood after an unexploded bomb was found during construction work in the Asian financial centre.

Explosive ordinance disposal officers were deployed to the scene in the city’s Wan Chai district.

Police diverted traffic, while shops and offices in surrounding towers were shuttered for the rest of Wednesday and ferry services at a nearby pier halted.

It’s the second time in less than a week a bomb has been unearthed at the site for a cross-harbour commuter rail link.

Bomb disposal experts identified it as an American-made 450kg general purpose bomb, the same type as one defused just days earlier at the site for a cross-harbour commuter rail link.

“However, there are some additional challenges” this time, said bomb disposal officer Alick McWhirter.

“The bomb is in dangerous condition. The fuse mechanism is severely damaged.”

He added that the bomb’s position made access difficult and the bomb disposal team was preparing to carry out stabilisation and disposal operations overnight.

Pictures on the Hong Kong police department’s Facebook page showed the bomb embedded in the side of a slope.

Both bombs are believed to have been dropped by warplanes during World War II, when the then-British colony was the scene of fighting between Allied and Japanese occupation forces.