Police were called to the Jobcentre Plus in Clifford Street in the Byker area in the east of the city on Friday morning to reports that several staff members were being held there.
Specialist negotiators were called in to deal with the knifeman involved, who is thought to have been known to the job centre.
About two and a half hours after the incident began, Northumbria Police said: "It is believed that all the hostages have been released and that the man concerned is the only person who remains in the building."