The flag of Niue was adopted in 1975.
The flag of Niue consists of the Union Flag in the upper left corner with a star in the middle of the Union Flag and four stars forming a diamond around it. It is very unusual for a flag based on a British ensign design, in having not only a yellow background, but also a defaced Union Flag in the canton. The yellow is said to represent the “warmth and friendship between Niue and New Zealand”. Wikipedia