The Port Authority administration building is located on the quay Rikard Kaarbø. This quay may also be referred to as the Dampskipskaia and Ekspedisjonskaia. Today the Express boats dock here. The quay complex was erected during the 1880s by Rikard Kaarbø. The Port Authority administration building, as it stands today, is from 1919 and was designed by the Harstad architect Sigurd Bjørhovde (1888-1959). The original administrated building was destroyed by fire in 1919. Large portions of the old brickwork were reused in the new building, thus the reconstruction process was quickly completed.

The administration building is rectangular in form and has a characteristic and vigorous style of architecture. The main façade is located on the short side and faces towards the town. It is symmetrically constructed and the centrally located entrance is marked with a monumental flight of steps and a roof dormer. The building has stylistic features from both the Neo Baroque and Jugendstil. The symmetry, the mansard roof, the monumental flight of steps and the use of imitation ashlars on the relief and corner terminations have Neo Baroque features. However, the oval windows are reflective of the Jugendstil.