Purpose – Interviewing victims of child sex abuse requires considerable care in order to minimise error. Due to children’s heightened suggestibility any question asked of a child could potentially incite error that could undermine the witness’s credibility. A focus group was conducted in order to facilitate the development of guidance for interviewers around the circumstances in which it is necessary to ask children follow-up questions in an interview. The paper aims to discuss these issues. Design/methodology/approach – Seven Crown prosecutors representing every Australian state and territory (with the exception of one small state) were issued with 25 hypothetical narrative accounts of child abuse and asked to indicate what information, if any, required follow-up in the child’s narrative. Their responses and rationale for requiring following up in some cases and not others were discussed. Findings – Thematic analysis revealed three recommendations to guide questioning: whether the case involved identification or recognition evidence; the presence of contextual features that may influence the witness’s memory, or that should trigger a particular line of questioning; and whether the information can or should be sought at a later stage by the trial prosecutor, rather than by the interviewer. Practical implications – The recommendations are discussed within the context of their implications for interviewing, that is, how each recommendation could be implemented in practice. Originality/value – The present study extends prior literature by elucidating principles to guide decision making across interview topic areas. The need for such guidance is highlighted by research suggesting that topics such as offender identity, offence time and place, and witnesses are a source of overzealous questioning in interviews.