Hemi Topine Te Mamaku (c. 1790 – June 1887) was a Māori chief in the Ngāti Hāua-te-rangi iwi from the Whanganui region of New Zealand's North Island.
Te Mamaku was born and raised in the Whanganui area and as tribal chief commanded a pā at Tuhua, at a strategic position on the Ohura River, north of Taumarunui. During the Musket Wars Te Mamaku was sometimes allied with Ngāti Toa chief Te Rauparaha and sometimes fought against him. However at the outbreak of the Hutt Valley Campaign in 1846 he was firmly on the side of Te Rangihaeata in resisting the encroachment of European settlers on to Māori land. On 16 May 1846 Te Mamaku led a force of about 200 warriors in a devastating dawn surprise attack on British troops at Boulcott's Farm in the Hutt Valley. Afterwards, he sent letters to other chiefs in the Whanganui area urging them to join in the conflict. Some were intercepted and forwarded to the government, which may have precipitated George Grey's decision to arrest Te Rauparaha.
Returning to Wanganui (then known as Petre) in September 1846, Te Mamuku told the 200 European settlers that he had no quarrel with them and would protect them from attack by other Māori, but that he would not tolerate the presence of government troops. Two months later, the government decided to station troops at Petre. In April 1847 four Māori were hanged for the murder of a settler family. Te Mamaku believed they should have been handed over for tribal justice. Raids on the outlying farms intensified and then, in May, Te Mamaku led a war party of up to 700 warriors that besieged the town. A significant battle ensued on 20 July, resulting in about a dozen casualties on each side and the eventual withdrawal of Te Mamaku's forces up the Whanganui River to the Pipiriki area.