In most instances Wireless Sensor Networks (WSNs) are confined to applications which require less security restrictions. This is because the trade-off between security and performance in WSNs is far too high. In this paper we explore the security requirements of the varied application fields of ZigBee WSNs from current to future applications with the aim of expanding the application domain, integrity and authenticity levels in such these applications. We will explore the existing WSNs security mechanisms and other security mechanisms which are available in wireless Adhoc Networks. Our aim is to harness the positive aspects of all the mechanisms and combine them to define a multilevel structured security which trades performance to security level. We believe with varied options in security and performance levels, ZigBee WSNs can adopt a wider applications domain. © 2010 IEEE.