All Polychaeta (Annelida) described from New Zealand in the 19th and early 20th Century are reviewed in an historical sequence from the first species described ‐ the serpuhd Vermetus cariniferus Gray, 1843, which was inadvertently classified as a vermetid mollusc ‐ to Dawbinia aucklandica, a species of problematical identity described by W B Benham in his last paper We organise the scattered information on purported New Zealand endemic polychaetes and their type localities, update information on the type repositories, and tabulate all taxonomic references to extrahmital species up to 1950 In comparison, taxa named since 1950 are less enigmatic and we briefly summarise taxonomic effort during this period We also tabulate New Zealand taxa described in the last two decades since the most recent catalogue Based on this taxonomic review we conservatively estimate the diversity of New Zealand's polychaete fauna as 53 families, 243 genera/subgenera and 471 species/subspecies, however, we recognise that the number of genera and, in particular, species will increase greatly following taxonomic revisions presently underway, or planned