It's a small butterfly, up to 33mm.
Here are the facts, more of which can be found on the TERRAIN website:
Species: L. salustius
Binomial name: Lycaena salustius
Common name: Common copper, Pepe Para Rki, Rauparaha's Copper
The Common Copper is said to be a short-lived butterfly, only known to live 1 to 2 weeks. There are 3 main variations in New Zealand, although even these vary throughout their respective ranges.
"Despite so many variations the Common Copper has a constant double wing vein marking in the centre of the hindwing, unfortunately this sometimes requires catching the butterfly to get a close enough look to determine this, especially on the females, where the double wing vein marking is almost blurred into each other. Common Coppers have a greater tendency to travel than other coppers, which are not generally found more then 20-50 metres from the larval food plant.
All the coppers are all suffering from Wasp predation, especially paper wasps, as they are a good source of protein for the wasp's developing larvae.
Attracting Common Coppers to your garden is fairly easy, just grow some Wire Vine - Pohuehue (Muehlenbeckia spp) and a plant a few nectar plants which have flowers at the end of stems as these are more favoured by the Copper Butterflies as landing sites."
(Ref: NZ Butterfly.info)
See also - Glade Coppers and Rauparaha's Coppers
I found my Common Coppers in the English garden of an historic home, at Wenderholm Regional Park.
The butterflies were so small, I almost overlooked them. Initially I thought I was seeing a browny-coloured moth, until I realised it was in fact a tiny butterfly.
There were several in the garden, so I followed them around the flowers, click, click, click.
The information I've seen, says they are found in warm, open places and that they're attracted to blackberry flowers.
The day I photographed them was hot and I found them enjoying the flowers in the garden. Just fabulous.