Terrible photo from a moving vehicle, but definitely a Dicranopteris of some sort.
Locally common along trackside. Associated with Blechnum novae-zelandiae and Kunzea tenuicaulis. Dicranopteris is however more common in the geothermal active portion of this reserve
Dicranopteris linearis is a common species of fern known by many common names, including Old World forked fern and uluhe (Hawaiian). It is one of the most widely distributed ferns of the wet Old World tropics and adjacent regions, including Polynesia and the Pacific. In parts of the New World tropics its niche is filled by its relative, Dicranopteris pectinatus.