New Zealand is increasingly using a Peer Review Panel (PRP) system for regulatory compliance of complex and contentious environmental infrastructure facilities, such as landfills. The PRP is a set of experts who serve as an advisor to the operator and the regulator, and are responsible to both parties for independent assessments. The PRP for the Kate Valley landfill facility is presented as a case study in the motivation for, and operation of, a PRP. The use of the PRP arises partly from the effects-based environmental legislation in New Zealand, which leads to a lack of standardization in construction/operation and unique permit conditions at each site. The PRP meets with operators on a regular basis, conducts site visits, receives relevant documentation, and prepares an annual report for regulatory authorities. The PRP is able to examine and discuss safety, financial, and operational issues with the operators while maintaining confidentiality. This allows for open discussions of these issues where they might impact on environmental performance. The PRP also assists operators by providing them with technical information and experience from outside the operator’s business environment. The PRP is a valuable option for regulatory bodies and project proponents to consider when developing permits for any one-off, complex facility with potentially large environmental impacts, and with great public concern.