Objective: To describe the approach undertaken to derive planning estimates for the mental health community support sector in Queensland, Australia.Methods: We quantified the needs for services by calculating the prevalence of mental illness in Queensland and by stratifying mental illness by severity. A taxonomy of services in the mental health community support sector was developed and target groups for services identified. Resource targets were set based on a review of the academic and grey literature, expert opinion and consultation with the funding body.Results: To provide adequate supported accommodation, 88 beds per 100,000 population are required, with 33.6 full-time equivalents (FTEs) per 100,000 population of attached personalised support. An additional 12.7 FTEs per 100,000 population of personalised support is required for individuals living independently in the community. We estimated that 6.9 FTEs per 100,000 population would be required for the provision of group support services. We estimated that a target of 1.6% of total mental health community support sector budget should be allocated to mutual support and self-help and 5% to community development.Conclusions: The mental health community support sector is now a major provider of services for people with mental illness, and is likely to continue to grow. When compared to public sector clinical mental health services, the mental health community support sector has lacked clarity surrounding what services are provided, and the quantity of resources required to provide these services. In the absence of other planning information for the community mental health support sector, the estimates described here provide a first step to guide governments and policymakers. Further research and testing in the real world by mental health community support sector practitioners is required to increase the evidence base and refine resource targets. [ABSTRACT FROM PUBLISHER]