The Reinga Basin occupies a northwest-southeast bathymetric d epression between the West Norfolk and Reinga ridges and has an area of about 100,000 sq. km. Rock samples have been dredged from surrounding ridges, but no boreholes have been drilled. We present a seismic stratigraphy developed using 5,135 line km of new 2D seismic-reflection data and 20,000 line km of older data, and we tie this stratigraphy to boreholes in the nearby Northland and Taranaki basins. We identify six phases of basin evolution. The first phase involved extension across northwest-trending normal faults. The region subsided passively during phase 2, and...