Morrison commended the efforts of staff who showed “extreme bravery” in restraining and securing the offender until police arrived, as well as providing first aid to their colleague.
Police said they found the alleged offender nearby and took them into custody without incident.
A cordon remained outside the service centre as of 1.30pm, with one officer standing guard and two police vehicles parked outside.
The office was closed for the day, and all staff were being supported, Morrison said.
“Our staff come to work every day to keep our communities safe and this sort of violence against our staff is unacceptable.
“We appreciate this would have been an extremely distressing incident for them and are offering them our full support.”
Hato Hone St John said it took the injured staff member “in a critical condition” to Whanganui Hospital. Police are investigating the circumstances of the incident.
Eva de Jong is a reporter for the Whanganui Chronicle covering health stories and general news. She began as a reporter in 2023.