Police temporarily closed the inbound section of Rama I Road outside their headquarters on Thursday after a security camera captured a man dropping a suspicious object at the fence.
Traffic police radio reported the closure of the section of Rama I Road near the Royal Thai Police head office to check a suspicious object at around 5.30pm.
Bomb disposal officers were called into the area to handle the situation as the roadblock caused traffic congestions on other roads, it said.
The roadblock ended an hour later after police confirmed that the object was not a bomb, it added.