 When New Zealand became a separate Colony from New South Wales in 1841, the Royal Charter established three provinces.The Porirua area became part of New Munster which included that part of the North Island south of the Patea River and the whole of the South Island.The British Parliament passed the first New Zealand Constitution Act in 1846 which reformed the provinces and the Porirua area became part of New Ulster which now included all of the North Island.