The Milford Leek-orchid is a deciduous terrestrial herb, with inflorescence growing from 50-80 cm tall. Flowers have white petals with green to purple markings and crinkled margins. The labellum is white, and sharply recurved at right angles near the middle, often protuding through the lateral sepals, which are greenish-brown and wide apart. The callus of the labellum is flesh, green and channeled centrally to extend just beyond the recurved bend on the labellum. The petals widen near their apex and are upswept and incurved, and approximately 6 mm long and 2.2 mm wide. Each flower is 9-12 mm long and 8-10 mm wide. The leaf of the Prasophyllum milfordense is dark green with a red to purple base, the free part 6-12 cm long.
Prasophyllum milfordense is part of the P. truncatum complex of orchids.