Residents have been given instructions on how to vacate their units for a controlled on-site disposal of a 50kg World War II aerial bomb war relic today.

The bomb, which was found at a construction site in Jiak Kim Street last Tuesday, will be disposed of between 8am and 6pm, by the Singapore Armed Forces Explosive Ordnance Disposal team.

A 200m cordon will be set up around the area during the operation.

The Singapore Police Force (SPF) said that all residents living in the affected area - which will include around 600 units - will be required to leave their homes before 8am and return only after 6pm.

Roads in the vicinity will be closed and residents, as well as guests and staff of a hotel, will be asked to evacuate.

The police will set up a temporary holding area for affected residents at River Valley Primary School at 2 River Valley Green.

"Loud sounds may be heard during the controlled on-site disposal of the war relic. The public is advised not to be alarmed," the police said.

Residents have been notified of actions they need to take, including leaving their windows open or slightly ajar and securing items in their homes. This is a precautionary measure in the unlikely possibility that windows might shatter due to pressure differences.

Pedestrians and residents are advised not to enter these areas while the bomb is being disposed of: Kim Seng Road (between the Singapore River and Havelock Road), Jiak Kim Street, and the footpaths along the Singapore River from Kim Seng Road to Saiboo Street.

More updates on the operation can be found on the SPF Facebook page, or by subscribing to the SPF WhatsApp broadcast by texting 9731-0950.