[3] A global phylogeny of Asplenium published in 2020 divided the genus into eleven clades,[6] which were given informal names pending further taxonomic study.

A. australasicum belongs to the "Neottopteris clade",[7] members of which generally have somewhat leathery leaf tissue.

While the subclades of this group are poorly resolved, several of them share a characteristic "bird's-nest fern" morphology with entire leaves and fused veins near the margin.

[5] A. australasicum grows on rocks or as an epiphyte on trees and is native to eastern New South Wales and Queensland.

[10] The clumps can reach a large size, with the centre of the fern acting as a reservoir for debris.