Following the Treaty of Waitangi on 6 February 1840, the Union Jack replaced the flag of the United Tribes of New Zealand as the official flag of New Zealand. The new Lieutenant-Governor, William Hobson, removed the United Tribes flag from the Bay of Islands and had the New Zealand Company's version of the flag hauled down at Port Nicholson.
Some Maoris felt the United Tribes flag should fly alongside the Union Jack, in recognition of their equal status with the government. The Union Jack was used on shore. At sea, New Zealand was represented by British naval or maritime flags until the United Kingdom’s Colonial Naval Defense Act became a law in 1865. The Union Jack remained New Zealand's flag until the passage of the New Zealand Ensign Act instituted the current flag in 1902.
It continued to be used regularly in New Zealand well into the 1950s, instead of, or in tandem with the New Zealand flag. Today, the Union Jack is most commonly seen in New Zealand when a member of the royal family, or another distinguished British guest, is visiting.
Royal Mail issued this stamp of Union Jack on 8th January 2008.