Coenogonium australiense is a species of corticolous (bark-dwelling), crustose lichen in the family Coenogoniaceae.

The type specimen was collected by the first author near Little Fisher River (Tasmania) at an altitude of 880 m (2,890 ft), where it was found in a rainforest growing on Nothofagus cunninghamii.

In the latter location it was found in remnant stands of coniferous woodland, where it was growing on the bark of old, fissured Callitris trunks.

[3] The thallus of Coenogonium australiense is crustose and varies in thickness, forming irregular patches on substrates.

Pycnidia are visible on the upper thallus surface as tiny pale swellings; the conidia are ellipsoid and measure 3–5 by 1–3 μm.