Aim of the study: to explore the skill mix requirements for the potential role of an unqualified midwifery assistant in the clinical setting. Using results from the study we report the difference between student midwives' and qualified midwives' perceptions of what constitute non-midwifery duties. Design: a two-round Delphi survey. Setting: large maternity hospital in Ireland. Participants: population of midwives (n=194) and midwifery students (n=79). Findings: the non-midwifery duties identified were wide ranging and could be categorised under the headings of clerical, stock, porter, domestic and other basic-care-related duties. Conclusion: although no agreed definition of non-midwifery duty exists it can be seen that, through the process undertaken in this study, a definition is created. This suggests that the values and beliefs that qualified midwives and students hold regarding their role shapes the role of the care assistant. Implications for practice: the inclusion of perceptions from student and staff midwives enabled the researchers to compare and contrast similarities and differences regarding how these different parties constitute a non-midwifery duty. The process also gave respondents a sense of ownership and involvement in the development of the midwifery assistant role. In addition, this study has demonstrated the need for further clarification of how midwives perceive and understand their role. (C) 2002 Elsevier Science Ltd. All rights reserved.