The emergence of the concept of unjust enrichment in New Zealand, its relationship to the remedial constructive trust and the development of the status of joint ventures in equity

From the 1970s onward there have been numerous attempts to persuade the courts of New Zealand that unjust enrichment might be an acceptable basis for imposing equitable remedies. The foundation for this proposition rests upon the supposed existence of a broad principle that the imposition of a constructive trust is justified in any circumstances where it would be against equity or good conscience to allow the retention of property by one who has an ostensible legal title. So the unjust enrichment, once established, becomes the cause of action and the constructive trust follows as an equitable remedy of a proprietary nature which is available to prevent the unjust enrichment. This has important ramifications for the development of the law pertaining to restitution in this country. This paper will show that the acceptance of the remedial constructive trust is linked to the development of a law of restitution founded upon the principle of unjust enrichment. It will also be shown that, while the roots of the conceptual distinction between law and equity remain intact, in many courts the practical ramifications of that distinction are being eroded, particularly in commercial cases