Sphaeropteris medullaris is found from sea-level to 600 m in lowland and hilly forests throughout the North Island and in the South Island of New Zealand from Marlborough Sounds and Nelson to southern Fiordland, on the west. On the east it extends to about Kaikoura, is rare on Banks Peninsula and is found sparingly in eastern Otago. It also occurs on the Three Kings, Stewart and Chatham Islands.
This is very much a water-demanding species, and the New Zealand districts in which it occurs are some of the wettest temperate rainforests in the world. Young plants can quickly fail with lack of water.
