Large-scale disasters have led the IASC to reform the humanitarian response system. After the 2004 Indian Ocean tsunami, an independent Humanitarian Response Review highlighted significant gaps in humanitarian response, including fragmented responses, duplication of efforts and insufficient engagement with government and national actors. Based on this, the IASC launched the Humanitarian Reform process in 2005. The aim of this major reform of humanitarian coordination was to improve the effectiveness of humanitarian response though establishing greater predictability in financing and leadership of responses, accountability to affected populations and partnership between UN and non-UN-humanitarian actors.

The cluster approach was one of the four pillars of Humanitarian Reform and was adopted by the IASC in 2005.