Emergency services have isolated a mysterious white substance delivered to Pipitea House for further testing.
The mysterious white substance was delivered to the Pipitea House in central Wellington at around 3pm on Monday.
The building houses the Government Community Security Bureau (GSCB) and the New Zealand Security Intelligence Service (SIS).
An area of the building was cordoned off as a precaution.
Police have confirmed they do not believe there is any further risk.
A New Zealand Intelligence Community spokesperson told NZME the powder had been delivered in an envelope.
Police are continuing to make enquiries.