Telephone counselling is a growing and complex task for district nurses in municipal home care, especially during evenings and at weekends. Work at call-time is often handled via telephone from cars, without access to records or other information about patients. There is a lack of research in this subject. The aim of this study was to explore preconditions for district nurses' telephone counselling at call-time. An observational study with an inductive approach was conducted. A structural protocol was used with a following open question. Seven district nurses who worked in home care in two municipalities in Sweden participated. Data were analysed using content analysis. Five categories were identified: 'availability', 'professionalism', 'communicability, 'secure approach', and 'technical approach'. Accessibility appears to be given priority over security. Ethical reflection is required on telephone management policy for district nurses' telephone counselling while driving and other interventions that require undivided attention.