They're on Beach Road between the Z petrol station and the intersection with The Strand and Parnell Rise, near entrances to the northwestern and southern motorways.
Waka Kotahi Transport Agency says the mainly two-storey buildings aren't suitable for commercial or residential tenants because they also contain asbestos.
A spokesman isn't sure if roads will have to be closed during the demolition, which will take 10 weeks.
The land was purchased in 2002 to improve transport access between the port and the motorways - work's scheduled to start in 2028.
