The Whare is the oldest standing structure on Kapiti Island and New Zealand's oldest building associated with nature conservation. However, the date of the building is not known. Historical evidence suggests that the building was in existence by 1880, and architectural evidence suggests that it may have been constructed earlier. This evidence includes the original shingle roof beneath the corrugated iron and shiplap weatherboards and joinery details which indicate a relatively early date of construction. On the other hand, Kapiti Island's relative isolation may have meant that more primitive building techniques were employed at a somewhat later date.

The Whare was built to provide accommodation for those involved in sheep farming on land leased from Ngati Toa. By the mid 1890s these and other associated activities had brought about such a drastic effect on the flora and fauna on Kapiti that the government was persuaded to legislate and purchase the island to protect its natural heritage. Although Ngati Toa objected, the Kapiti Island Reserve Act was passed in 1897. Pakeha leaseholders were compensated and Ngati Toa retained 526 hectares at the northern end of the island, which they hold to this day. The Whare became the home of successive caretakers, including Richard Henry who was New Zealand's, and possibly the world's, first state-sponsored conservation officer when he was appointed to Resolution Island in 1897. It was there that Henry pioneered techniques of capture and transferral of endangered birds such as the kakapo.

After a caretaker's house was built on the island (c.1913-1924), the Whare was used to accommodate visitors to the island. Such visitors included Governors-General, judges, ambassadors and diplomatic staff, Ministers of the Crown, and some of New Zealand's most important ornithological and botanical scientists. The Department of Conservation now conserves the Whare as part of its overall management of the island. In 1998, as part of a programme of conservation work, it restored the verandah, which may have been removed as early as 1906 when the building was damaged in a storm. The original verandah post-holes were relocated using archaeological techniques.

The Whare has significance as the oldest building on Kapiti Island, for its association with early farming activity on the island and with early conservation of flora and fauna. Some of the most notable names in New Zealand conservation have stayed in the house, as have a number of visiting dignitaries. Although once situated in open pasture, today the Whare is surrounded by regenerating bush. Nevertheless, it sits very well in its landscape.