A man threatened staff at the Forex exchange office, which remained closed on Friday afternoon, and left a package on the counter, a police spokesman said.
The whole of the Klarabergsgatan street was closed while police dealt with the package. The Forex currency exchange office and nearby premises were evacuated and bomb technicians were called to the site.
"There is a discussion about whether to examine the package on site or to remove it to a different location," police spokesperson Eva Nilsson told news agency TT as bomb technicians carried out their investigation.
Tom Friberg, head of communications at the Forex Bank said there had been no threats to the currency exchange before Friday's incident.