IntroductionNew Zealand (NZ) has a persistently high rate of suicide, particularly among young people. Hospital presentation for self-harm (SH) is one of the strongest predictors of death by suicide. Improving the monitoring of SH and suicide is a key recommendation for suicide prevention by WHO. This study will establish the first ever sentinel surveillance for SH at several large hospitals and a monthly survey of all practicing paediatricians in NZ. The study will provide robust information about the epidemiology of SH, factors associated with SH and the types of interventions required for those presenting to hospital with SH.Method and analysisThis observational study will establish SH surveillance in the emergency departments of three public hospitals for the first time in NZ, where study population will include individuals of all ages who present with SH or suicidal ideation. The study methodology is in line with the WHO Best Practice guidelines and international collaborators in Australia and Europe. Electronic triage records will be reviewed manually by the research team to identify potential cases that meet inclusion criteria. For all eligible cases, variables of interest will be extracted from routine clinical records by the research team and recorded on a secure web-based survey application. Additionally, SH surveillance data for the national paediatric population (<15 years) will be obtained via the New Zealand Paediatric Surveillance Unit (NZPSU); paediatricians will report on included cases using the same variables using a secure survey application. A deidentified dataset will be produced for aggregated statistical analysis.Ethics and disseminationThe University of Otago Health Ethics Committee granted ethical approval for this study in addition to local ethics approval at participating hospital sites. The study findings will be disseminated to relevant stakeholders in NZ, in addition to international audiences through publications in peer-reviewed scientific journals and conference presentations.