Suicide and intentional self-harm are issues of major importance in public health and public policy, with rates widely used as progress indicators in these areas. Accurate statistics are vital for appropriately targeted prevention strategies and research, costing of suicide and to combat associated stigma. Underreporting of Australian suicide rates probably grew from 2002 to 2006; Australian Bureau of Statistics (ABS) suicide data were at least 11% or 16% undercounted (depending on case definitions) in 2004. In coronial cases with undetermined intent for 2005 to 2007, intentional self-harm was found in 39%. Systemic reasons for undercounting include: (i) absence of a central authority for producing mortality data; (ii) inconsistent coronial processes for determining intent, as a result of inadequate information inputs, suicide stigma, and high standards of proof; (iii) collection and coding methods that are problematic for data stakeholders; and (iv) lack of systemic resourcing, training and shared expertise. Revision of data after coronial case closure, beginning with ABS deaths registered in 2007, is planned and will reduce undercounting. Other reasons for undercounting, such as missing or ambiguous information (eg, single-vehicle road crashes, drowning), differential ascertainment (eg, between jurisdictions), or lack of recorded information on groups such as Indigenous people and gay, lesbian, bisexual and transgender people require separate responses. A systemic coordinated program should address current inaccuracies, and social stigma about suicide and self-harm must be tackled if widespread underreporting is to stop.