Common Blue butterfly (Zizina otis spp.labradus)
Species: Z. otis
Sub species: Z. o. labradus
Binomial name: Zizina otis ssp. labradus,
Synonym: Zizina labradus labradus
Common name: Common Blue, Pepe Ao Uri
Zizina otis ssp. labradus is probably our most common butterfly (originally wind blown from Australia) It is a small butterfly (up to 23mm wingspan) with a weak, fluttering flight and so it usually flies close to ground level close to a food source. In some areas it is considered a pest species as one trail recorded over 300 larvae per square metre on drought-prone pasture.
They lay a single eggs which are laid and can hatch in a matter of days. The eggs are laid on leaves, stems, flower buds and young pods of food plants, chiefly legumes of the Fabaceae family such as beans, clover and various native species. Newly hatched larvae eat small holes from young leaves or flower buds, and later feed mainly inside flowers.
For more details visit: http://nzbutterfly.info/downloads/nzButterfly.info-factsheet-common-blue.pdf
They certinaly like the flowers of Sedum. The next two photos are of the same butterfly.