Douglas Sinclair was born in Dunedin and attended a number of schools including St Patrick’s in Newtown, Wellington, and Rangiora High School. During the Second World War, he served overseas with the 28th Māori Battalion and on his return to New Zealand studied medicine at Otago University, graduating MBChB in 1952.
In 1952 he was offered an opportunity to become a member of the Fellowship of the Royal Australasian College of Surgeons but was unable to put together the finances to make this an actuality. In 1970 he gained a Diploma of Obstetrics from Auckland University. Sinclair worked as a General Practitioner in Tolaga Bay and later in Hamilton. He took great pride in his care for his patients and was well-liked by his patients. He moved to Australia where he helped set up Aboriginal Health Clinics; he took a keen interest in the health education and land issues of the Aborigines he worked with.
Sinclair was deeply interested in whakapapa, waiata, Māori myths, legends and traditions and te reo Māori. He was also passionate student of Māori medicine, greenstone carving, growing taha for carving, the Treaty of Waitangi, Māori Land Issues, Māori Health, Education and Māori Representation in Parliament. Many of these issues later dominated his thoughts and actions and led to him being dubbed an activist. He became Chair of Te Matekite, played a major role in the return of the Raglan Golf Course, and challenged Town and Country Planning Acts. He pressed for greater Māori Representation in Parliament, recognition of the Treaty of Waitangi and for Māori to take greater control over their lives. He attended Indigenous Peoples’ Conferences and presented the Indigenous Peoples’ Charter which later became the Charter for Whaingaroa. He was involved in politics and Māori health and Treaty of Waitangi issues. In the 1969 elections, he contested the Raglan seat for the Labour Party and was selected again in 1972. Sinclair was a founding member of Māori Graduates’ Association and was president of the Tainui branch of the Māori Graduates’ Association. He was on the Board of Governors of Ngata College and was on the Hawkes Bay Education Board.
Sinclair was a member of various Māori incorporations and was a member of Ngāi Tahu Trust Board at various times. He was involved in Ngāti Hamutana, was a member of Waikato Credit Union, was a rotarian and member of the Executive of the New Zealand Multiple Sclerosis Society. He died in Brisbane on October 29, 1984 and is survived by his wife Manu, four daughters, two sons and nine grandchildren.
- Correspondence and phone conversation with Waiki Edward, 5 July, August 1998.
- Te Māori: The Official Journal of the New Zealand Māori Council 1.2 (1969?):15.
- Te Ao Hurihuri: Aspects of Māoritanga. Ed. Michael Smith. Auckland, N.Z.: Reed, 1992. 5.
- "Tolaga Bay And Its District High School: A Survey Of The Tolaga Bay Community (Part 1)." Te Ao Hou 26 (1959): 6-9.
- In this detailed study of Tolaga Bay Sinclair discusses its Māori history and the impact of European settlement on the region. After huge blocks of land were sold to settlers Sinclair writes that Māori had to learn how to acquire capital and how to make their capital work for them. The East Coast Lands and Settlement Company was established to assist the region to obtain sufficient capital to develop the land. Sinclair observes that while Ngata’s scheme for developing Māori lands with funding from the Māori Affairs Department was very successful in unlocking large tracts of Māori lands, there was not sufficient land in Tolaga Bay to take advantage of this scheme. Instead the Whangara Incorporations, the East Coast Commission, the Tairawhiti Māori Land Board and Waru Estate trustees effectively developed land in their control.
- "Tolaga Bay And Its District High School: A Survey of the Tolaga Bay Community (Part 2)." Te Ao Hou 29 (1959): 25+.
- Sinclair examines the Tolaga Bay Māori population shifts from European settlement to the post Second World War era. In assessing employment prospects in the Tolaga Bay region, Sinclair notes the almost limitless supply of rural work for men and limited employment opportunities for women. He traces the history of the Tolaga Bay School and identifies educational needs in the community.
- "Pounamu: The Rape of the Jade Fish of Ngahue." Rongo 1.1 (Summer 1973/74): 18.
- In this article Sinclair assesses the impact of European settlement on the Māori in terms of land loss and argues that there were many cultural losses which accompanied dispossession of tribal land. He examines specifically the impact of the ‘enforced sale of the seven million acre West Coast to the Crown’ in the 1860s on the pounamu carving traditions. He describes the Māori reverence for pounamu, the tapu laws governing it, the guardians of the pounamu and the varieties of pounamu. He concludes by advocating that ‘the time has come to hand back the rights of the greenstone together with the land stolen... [and to] set up a school of Māori carving in jade, [and] recapture the old traditions...’
- "Land: Māori View and European Response." Te Ao Hurihuri: The World Moves On. Ed. Michael King. Wellington, N.Z.: Hicks Smith & Sons, 1975. 115-140. Rpt. in Te Ao Hurihuri: Aspects of Māoritanga. Ed. Michael Smith. Auckland, N.Z.: Reed, 1992. 64-83.
- In this extensive essay on the Māori relationship with the land Sinclair recalls Māori creation stories and traditional systems of land tenure under the headings: Customary Title or Papa Tipu, Right of Discovery or Whenua Kite Hou, Right of Occupation or Ahi Ka, Right of Conquest or Take Raupatu, Right of Gift or Take Tuku, Right of Deathbed Deposition or Take Ohaki and Law of Compensation for Misbehaviour or Muru. He writes of the process where Māori customary land came under Crown Title from the 1840 onwards and looks at the system of land tenure which was introduced by the New Zealand Company and Hobson with its shift from humanitarian concern for the welfare of the Māori to ‘strictly commercial’ concerns. Sinclair discusses the Treaty of Waitangi and assesses the results of the pre-emptive clause of the Treaty and how this monopoly forced Māori land to be sold at depressed prices and resold to the European settles at vastly inflated prices.
- "Land Since the Treaty: The Nibble, the Bite, the Swallow." Te Ao Hurihuri: The world moves on. Ed. Michael King. Wellington, N.Z.: Hicks Smith & Sons, 1975. 141-172. Rpt. as "Land Since The Treaty." in Te Ao Hurihuri: Aspects of Māoritanga. Ed. Michael Smith. Auckland, N.Z.: Reed, 1992. 84-104.
- A detailed chronological study of legislation and actions by the New Zealand Company, governors and land courts to divest Māori of their land from 1840 to 1967. This essay examines the background of land disputes in Wairau, the Hutt Valley, and Taranaki and the resulting confiscations. This comprehensive account was written prior to the introduction of the Waitangi Tribunal.
- "Māori Candidates in Non-Māori Seats: How does it feel to be a candidate in such a seat?" G. V. Butterworth. Te Māori: The Official Journal of the New Zealand Māori Council 1.2 (Spring Issue [1969?]: 15-18.
- Te Māori editor. G. V. Butterworth interviews Sinclair, a Labour candidate for Raglan, on his electoral chances in the 1969 general election and he also interviews Koro Wetere and William Edwards.