From Danny Keenan, 'New Zealand wars - Gate Pā, Tauranga', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/en/new-zealand-wars/page-7 (accessed 15 October 2020):
In January 1864 Governor George Grey reassigned several British contingents to Tauranga in order to impede the flow of arms and men of Ngāi Te Rangi and Ngāti Ranginui to the Waikato. Upon hearing that British troops had arrived in Tauranga, the men, led by Rāwiri Tuaia Puhirake, immediately returned home from the Waikato.
By April 1864 Puhirake had assembled 250 Māori at Pukehinahina (Gate Pā), determined to resist further British encroachment. On 29 April Lieutenant General Duncan Cameron ordered an attack upon Pukehinahina, commencing with an artillery barrage. Once shelling was seen to have breached the front palisade, an infantry assault followed. British assault parties broke through the palisades, engaging with concealed Māori who fired from a network of underground trenches. The British suffered heavy casualties, and were soon in retreat.
A second assault proved equally unsuccessful. During the night, British soldiers lying wounded in the field were tended by Māori, notably Hēni Te Kiri Karamū, a young woman from the pā. Under cover of darkness, most Māori escaped during the night. When the British resumed their assault next day, they found that the pā had been abandoned. Thirty-five British regulars died during the engagement, with another 75 wounded.