This focus of this thesis is on the seismic stratigraphy and structure of the part of North Taranaki Basin immediately north of western Taranaki Peninsula, central-western North Island. In particular, the emphasis is on basin geometry and sedimentation patterns of the Late Cenozoic section. The seismic mapping has been undertaken with open-file industry data archived by New Zealand Petroleum and Minerals (MBIE, Wellington) using industry-standard software (Kingdom TM) under an academic Licence to The University of Waikato. Seismic reflection mapping made use of 175 2-D seismic profiles and one 3-D seismic survey (Parihaka), all acquired over 6350 km2 in the study area. Fourteen drill holes in the study area penetrate at least the L. Cenozoic section and from them biostratigraphic data have been previously generated and reported in Petroleum Reports and in papers. An age model has been generated from these data that relies especially upon New Zealand biostratigraphic stage boundaries located in Ariki-1 and Arawa-1, where there is highest confidence about their placement. These are (i) top of Kapitean (5.3 Ma), top of Opoitian (3.6 Ma), top of Waipipian (3.0 Ma), top of Mangapanian (2.4 Ma), and top of Nukumaruan (1.63 Ma). The depths in all 14 drillholes of the newly mapped seismic horizons are illustrated in an enclosure (No. 1) in relation to the biostratigraphic stage boundaries, which documents the age model for the Pliocene-Pleistocene succession in Northern Taranaki Basin. From seismic mapping of horizons selected close to the biostratigraphic stage boundaries (Ariki-1 and Arawa-1), a series of structure contour and isopach maps have been generated for the study area. Parihaka Fault is a major structure revealed by the seismic mapping. It is a segmented fault that bounds a half-graben structure named the Arawa Sub-basin. A second enclosure illustrates this and other structures (e.g. buried volcanoes) on selected seismic reflection profiles and in the structure contour and isopach maps. The Arawa Sub-basin and Northern Graben developed during the later part of the Kapitean Stage (Late Miocene); that is, prior to 5.3 Ma. Sediment distribution patterns in the Opoitian Stage (Early Pliocene) section were very much influenced by the location of depocentres formed during the Late Kapitean. The Waipipian (Mid-Pliocene) section is comparatively thin and represents a slow down in the sediment supply to North Taranaki Basin, probably because the material being sourced from erosion of the Southern Alps was captured by Wanganui Basin and Toru Trough in southern Taranaki Basin. During the Mangapanian Stage (Late Pliocene) there was a marked increase in sediment flux to North Taranaki Basin, which resulted in the infilling of Arawa Sub-basin and the formation of a well-defined continental shelf-slope margin, which prograded to the northwest. The Nukumaruan Stage (Early Pleistocene) together with the rest of the Pleistocene was characterised in the study area by further progradation of the shelf-slope basin and a re-orientation of it towards the northwest, forming the modern shelf and slope bathymetry.