This New Zealand stamp is known as the "Universal" and was printed in very large numbers between 1901-8, much like the USA's green Ben Franklin 1c (Sc#300). Looks like a printing from a worn plate, such as what Vayolene shows.
As with many classics, the stamp has been extensively studied. It was printed on different papers by different printers and there are constant distinguishing plate varieties. The cancellation is probably Blenheim.