High Quality Content by WIKIPEDIA articles! This Wairoa River is located in the north of the South Island of New Zealand. It flows north for 45 kilometres before combining with the Wai-iti River to form the Waimea River. This flows into the southern end of Tasman Bay near Richmond.The South Island (M ori: Te Wai Pounamu) is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean. The territory of the South Island covers 151,215 square kilometres (58,384 sq mi) and is influenced by a temperate climate.