During 1992 a new Mental Health Act was implemented in New Zealand. The Act created a new role, that of the duly authorised officer (DAO) which has been mainly carried out by community mental health nurses. During 1994 a multisite qualitative research study was undertaken to describe the newly structured mental health nursing role and examine the issues related to it. A key issue which emerged was the concern that the nursing role had been defined and resourced by other groups (legal, medical and management) on the basis of its visible tasks rather than the invisible components of professional nursing knowledge and expertise. The legal descriptions of the DAO role negated the highly developed assessment skills of mental health nurses, suggesting that nurses are there for advice and assistance. Yet expert clinical judgement was pivotal to the effective functioning of the new role. This paper argues that the initial nursing mental health crisis assessment which is carried out in the community is a highly skilled nursing activity which must be recognized and resourced accordingly.