Aims and methodThis study examined the frequency of seclusion intervention and factors associated with its use in the acute general adult psychiatric ward serving the Southland area of New Zealand. Details of the use of seclusion and relevant demographic data were collected over a 12-month period in 2007–2008.ResultsDuring the study period there were 30 seclusion episodes involving 23 patients. The median duration of seclusion was 17 hours. The duration of seclusion was found to be inversely related to the treatment received during the period of isolation. Most patients under seclusion had a diagnosis of psychosis, and the nature of this was directly related to the Mental Health Act order applied.Clinical implicationsThe duration of seclusion in this study is long but compares with a similar study from elsewhere in New Zealand. The duration of treatment while in seclusion could be reduced if optimal treatment is given.