Telecom is to build new a Wellington headquarters housing 1700 personnel in the central city.
The building on Willis Street will bring together people working at six locations in the city.
But not all Wellington personnel will be based there. Those working for an operationally separate network unit, Chorus, will remain in separate offices.
The building is due to be completed by mid-2011, a year after Telecom's new building in Auckland is due to open.