New Zealand marine fishing activities create many types of environmental externalities, which by law must be internalised. Selection of best internalisation instruments can be aided by following a hierarchical decision process, which first screens the universe of instruments against implementation criteria to establish the feasible set. Instruments in the feasible set can be evaluated against a range of environmental, Treaty of Waitangi, economic, sociocultural and management criteria. This approach to selection can be formalised in decision support software to provide a useful tool for fisheries management agencies.