The four-story building at 190 Nathan Road is one of three remaining pre-war buildings with corridor-style balconies and is located at the corner of a block - opposite Kowloon Park.

The other two such buildings are on Prince Edward Road West in Kowloon and Stewart Road in Wan Chai.

The move to possibly give the WW2 building a grade one heritage status came after the owner of what was listed as a grade III historic building in 2018 was given the green light to demolish the structure last year.

Conservationists also argue it would be wrong to tear down the Nathan Roadblock as it is one of the few remaining civil buildings occupied by the Japanese army during World War Two.

Previously, groups including Walk in Hong Kong and the Urban Studies Institute, along with history experts, point to the building being a restaurant before WW2 and its Chinese American family owners being forced to become servants of the Japanese military. And two sons of the family monitored the movements of Japanese military ships and activities at Japanese barracks from the building's balconies and rooftops and passed on information to the British.

The Japanese eventually discovered their activities and killed them.

The preservation camp says such history reflects a historical value in how Hongkongers resisted. 

The conservationists earlier requested the Antiquities Advisory Board to upgrade it to a grade I historic building. According to the grading system of the Antiquities Advisory Board, grade I buildings hold outstanding merit and should be preserved if possible. But grade III buildings are not qualified for consideration as monuments and can be demolished.