Upper Hutt Police are at an address in Wallaceville where a package containing a white powder was discovered earlier this morning.
Incident Controller, Senior Sergeant Anita Dixon says a staff member of a building located in Lane Street, discovered an envelope containing white powder around 9:15am. As a result, emergency services were called and have cordoned off the premises.
"About 20 of the 40 staff at the premises are currently being decontaminated. However, no one is exhibiting any signs of illness at this stage."
Senior Sergeant Dixon says the package has been contained and removed by Fire Service staff and is currently being examined by Environment Science and Research (ESR) to determine what the substance is. It's expected this process will be completed by early this afternoon.
Emergency services will remain at the scene until it is deemed safe for staff for re-enter the premises. An investigation will then get underway to identify the person or persons responsible for sending the envelope.