Peter trained as a lawyer and has specialised in environmental management issues since the 1980s. He taught at Massey University's School of Resource and Environmental Planning focusing on environmental law, environmental planning, natural resource planning, and conservation policy and has been a professional teaching fellow in the University of Auckland's Planning Department teaching graduate courses. Since 2000 he has worked with US based universities on study abroad programs focusing on environmental policy and governance; culture, identity, and place; knowledge systems and ways of knowing; community empowerment strategies and comparative social movements. He is an active advocate, researcher, and consultant on collaborative management strategies between Māori and the New Zealand government and has served as a consultant to Māori in the design and implementation of management plans for land and sites that are sacred or represent cultural heritage.