Onamalutu Campsite is a DOC conservation campsite set within the Onamalutu Scenic Reserve, roughly 30 minutes' drive from Blenheim in Marlborough's South Island.

The reserve sits in the Onamalutu Valley, and its name is actually a mispronunciation of Ōhinemahuta — the river that flows through it.

The reserve was established in 1901 when a local sawmill operator donated a surviving stand of ancient podocarp forest for public recreation.

The campsite occupies spacious grassy flats bordered by remnant native forest dominated by kahikatea, tōtara, and matai — species that became rare in the region following widespread 19th-century deforestation.

Facilities include flush toilets, a stainless-steel sink, tap water (boil water advisory applies), and picnic tables. Fifty unpowered tent sites and four powered sites are available.

Several short walking tracks wind through the forest, and the Ōhinemahuta River is accessible via a brief forest walk. Sandflies and wasps (particularly in late summer and autumn) are worth preparing for.

The Wakamarina Track begins about 8 km from the campsite.