The use of post-earthquake cordons as a tool to support emergency managers after an event has been documented around the world. However, there is limited research that attempts to understand the inherent complexities of cordoning once applied, particularly the longer-term impacts and consequences. This research aims to fill the gap by providing a detailed understanding of cordons, their management, and the implications of cordoning in a post-earthquake environment. We use a qualitative method to understand cordons through case studies of two cities where cordons were used at different temporal and spatial scales: Christchurch (M6.3, February 2011) and Wellington (M7.8 in Kaikōura, November 2016), New Zealand. Data was collected through 21 key informant interviews obtained through purposive and snowball sampling of participants who were directly or indirectly involved in a decision-making role and/or had influence in relation to the cordoning process. The participants were from varying backgrounds and roles i.e. emergency managers, council members, business representatives, insurance representatives, police, and communication managers. We find that cordons are used primarily as a tool to control access for the purpose of life safety and security, but cordons can also be adapted to support recovery. Broadly, our analysis suggests two key aspects, ‘decision-making’ and ‘operations and management’, which overlap and interact as part of a complex system. The underlying complexity arises in large part due to the multitude of sectors affected by cordons: economics, law, politics, governance, evacuation, civil liberties, available resources etc. The complexity further increases as the duration of cordoning is extended.