Cyrtostylis oblonga is a terrestrial, perennial, deciduous, herb with a single heart-shaped to almost round leaf 10–40 mm (0.4–2 in) long and 8–17 mm (0.3–0.7 in) wide.

The petals are similar in size and shape to the lateral sepals.

The column is shorter than the labellum and has two wings widening towards the tip.

[2][3] Cyrtostylis oblonga was first formally described in 1853 by Joseph Dalton Hooker in Flora Novae-Zelandiae.

[4][5] The specific epithet (oblonga) is a Latin word meaning "longer than broad".