Mānuka joined the University of Auckland Business School in 1996 and is Associate Professor in Māori Business Development in the Department of Management and International Business and recently completed (December 2014) a twelve year term as Associate Dean (Māori and Pacific Development). Mānuka is also the foundation Director of the Mira Szászy Research Centre for Māori and Pacific Economic Development and leads a number of multidisciplinary research project teams.
He is board member of the University of Auckland Centre of Development Studies, and the Centre of Pacific Studies and was until 2013 the Academic Coordinator of Te Tohu Huanga Māori Graduate Programme in Business Development within the Graduate School of Management and teaches Māori business and economic history, strategy, and management of tribal enterprises.
In 2014 he was appointed a member of the Royal Society of New Zealand Humanities and Social Science Advisory Panel. He has advised government departments, local authorities and other institutions on ambicultural or bicultural governance and management policies and also served on government advisory committees on development assistance, peace and disarmament, archives, history, social policy, environmental risk management and number of other ministerial appointments. He was previously a lecturer in Māori studies at Victoria University of Wellington, where he taught courses on the Te Tiriti o Waitangi/Treaty of Waitangi, Māori culture and society and tribal histories.