Coprosma tenuifolia is a small dense fast growing native shrub with large green/red leaves and with a spread up to 3m. It has stout, glabrous, ascending, branches and branchlets. Branchlets green streaked with purple,

It has an altitude range: 610–1280 m. The leaves rapidly tapers to a wingless petiole 10–25 mm long, glabrous except on upper surface midvein; lamina ovate to oblong, mottled dark and mid-green with red to purple blotching often present, particularly visible on the lower leaf surface, membranous to thinly coriaceous; apex acute or apiculate; margins crenulate and slightly undulate, with antrorse hyaline hairs; upper midvein and reticulated veins visible on both sides of leaf, short erect hairs on upper surface midvein extending from base to near apex; domatia present. It flowers during November – January and fruits during March-May. Flowers are unisexual, in leaf axils, a short peduncle c. 3 mm long with 3 flowers sessile at the peduncle apex. The fruits are orange, ovoid, 7–8 mm long. The seeds are 2 per fruit, 4.3–6.7 mm long, 2.2–3.7 mm wide. The female produces the fleshy berries which attract birds.