Matthew has a broad public and commercial law practice, encompassing regulatory, Māori, human rights, class action and environmental law. He has special expertise in judicial review and in the use of public law tools to achieve legal, regulatory and policy outcomes.

Matthew has done legal work across a range of sectors of the economy and he has acted for individuals, for entities of many kinds (including companies, incorporated societies, Māori incorporations and trusts), for Crown and public sector bodies (including Ministries, Crown entities and commissions of inquiry), for industry groups and for NGOs.