Top-down, centralised approaches to reform of mental health services implemented over the past 15 years in Australia have failed to achieve the widely shared aim of comprehensive, integrated systems of care. Investment to date has focused on the development and integration of specialist mental health services and primary medical care, and evaluation research suggests some progress. Substantial inadequacies remain however in the comprehensiveness and continuity of care received by people affected by mental health problems, particularly in relation to social and psychosocial interventions. Intersectoral collaboration that includes the diverse range of non-medical primary health and social care services is one of the most fundamental remaining challenges facing mental health system reform.