Gunnera prorepens is endemic to New Zealand, and occurs in lowland to subalpine regions of the North, South and Stewart Islands from Auckland southwards. It is a herbaceous plant that forms wide-spreading mounds of vegetation in boggy and damp places in forest, sphagnum bogs, herbfields, and grasslands in lowland to montane areas. It will grow in both shade and sun, and when growing in the sun, its foliage colour becomes quite intense with the onset of cold weather. The very distinctive brownish to purple-green to green leaves are oval, typically 3 cm long, and carried on long stalks. Male and female flowers are found on separate plants. The bright red fruits develop on a 10 cm tall spike and ripens in late summer.