These 3 stamps are from 2009 Matariki (Maori Year) issue beginning from Jun.24,2009.
Matariki is a traditional Maori festival to celebrate and to prepare the ground for the coming year. Offerings of the produce of the land were made to the gods, including Rongo, god of cultivated food. This time of the year was also a good time to instruct young people in the lore of the land and the forest. In addition, certain birds and fish were especially easy to harvest at this time.
This year New Zealand Post honours heitiki as an icon of Maori art.
The hei-tiki is an ornamental neck pendant of the Māori. Hei-tiki are usually made of greenstone and worn around the neck. One theory of the origin of the hei-tiki suggests a connection with Tiki, the first man in Māori legend. There are two main ideas behind the symbolism of hei-tiki: they are either memorials to ancestors, or represent the goddess of childbirth.