The primary focus of this thesis is to examine the extent to which New Zealand law enables effects of activities to be controlled for the purpose of preserving the integrity of an organic farm. In particular the thesis examines the impact of contaminant discharge, emanating from non-organic farming activities, in the form of agrichemicals and genetically modified organisms ( GMO ). Both types of discharge pose a serious threat to the continued existence and development of organic farms in New Zealand. The thesis explores the nature of the threats and possible approaches to resolving conflicts between organic and non-organic farming. The issues raised are of contemporary importance, and although land use conflict has been thoroughly considered by courts and commentators, this particular conflict has not received the same degree of attention. The increase in organic farming and the introduction of GMO into the New Zealand environment are factors, which give impetus to the need to explore ways in which to resolve any conflict. In New Zealand organic farms can be certified, pursuant to several different schemes, to provide an assurance that product has been produced in accordance certification standards. Those standards generally place restrictions upon the use of artificial substances and GMO. Organic farms are commonly located alongside non-organic farms, and therefore organic farmers must ensure that there is no incursion by these substances across the boundary of an organic farm. The thesis examines the extent to which non-organic farmers can be constrained in relation to the emanation of contaminant discharge. It identifies internalisation of effects as being of critical importance to the continued existence and development of organic farming within New Zealand. Theoretical justifications are examined, and support for a requirement for internalisation of effects, which cause decertification, is identified from different sources including an economic approach, arguments from property rights, ethical duties to the environment and the tort liability theory of outcome responsibility. A critical issue that threatens the preservation and viability of the organic farm is whether the organic farm can be termed a sensitive activity, thereby reducing the right to protection by the law. At common law, sensitivity represents an obstacle to recovery for loss suffered in both negligence and nuisance. The thesis explores the application of the concept of known vulnerability as a means by which to overcome the notion of sensitivity, as well as considering other theoretical justifications. It suggests evolution of the law, so as to preserve the opportunity to farm organically in New Zealand, and thus be in step with leading international initiatives to promote organic farming. The research examines the statutory framework, and it is contended that in order to achieve integrated management of resources the RMA should be used in conjunction with HSNO to regulate the effects of hazardous substance and new organisms. The RMA is identified as a primary measure capable of providing effective protection of an organic farm. A requirement for internalisation of effects is recognised as the most flexible method to secure co-existence of conflicting activities.