Mill Arm Campsite is a remote DOC basic campsite located near the head of Mill Arm in Greville Harbour on D'Urville Island, in the Marlborough region of New Zealand's South Island.

The site offers four flat, non-powered tent sites with stunning views of the surrounding landscape. Access is by boat only, departing from Nelson, Te Aumiti/French Pass, or Havelock.

Facilities are minimal, with non-flush toilets and water sourced from a nearby stream. Camping is free and operates on a first-come, first-served basis year-round. Fires are not permitted at any time, and dogs are not allowed.

Visitors should be aware that the stream is prone to flooding during periods of heavy rainfall. The area provides good opportunities for fishing, hunting, and tramping in the surrounding scenic reserve.