An e-Government portal represents not only a public image of a sovereign region, but also a reliable service platform for many users from local citizens and beyond. This makes the requirement for robustness of e-Government portal relatively stringent. In view of this, it would be very useful to have an independent server that serves as a 24/7 watch-guard to monitor the performance of the service portal. In this paper, we proposed a Web-based performance monitoring system (WMS) for checking the health status of the service portal in real-time. Some basic server information is usually provided by the web hosting service provider. Usually these information are simple statistics such as the number of hits and server loads over a selected period of time. Further details regarding the performance of the portal however may not be available or they come at expensive prices. This service is provided either by some third-party proprietary commercial software tools on the market or through consultancy services. The proposed WMS provides additional performance checks with the advantage of open source and Java based implementation platform. It features web usage mining from web log files in addition to the statistics offered by the hosting company. A higher level of analytical insights can be obtained too when the two are combined. The functions of WMS include: Web Log Analysis, Web Usability Analysis, Website Performance Benchmarking, Web Link Validation, and Performance Reporting. WMS can be used as a generic monitoring tool for virtually all kinds of e-business models. Specifically, we discuss the context of applications of WMS to e-Government performance models.