Astelia chathamica, the Chatham Islands kakaha, Maori flax, or silver spear, is a species of flowering plant in the recently named family Asteliaceae.

It is an evergreen silver-green perennial from the Chatham Islands of New Zealand, growing to about 1.2 m (4 ft) tall.

Forming a large clump of sword-shaped leaves, it produces small green flowers and red berries (the latter only on the female plant).

It grows best in partial shade and in fertile and well-drained soil with moderate water.

In cultivation in the UK, this plant has gained the Royal Horticultural Society's Award of Garden Merit.