E-government has brought a lot of opportunities to public services. However, alongside opportunities, there are many challenges with e-government implementations, one of which is security. Security incidents in e-government have resulted in loss of money, revenue, resources and trust by the users of the systems. There are a number of possible measures to mitigate such security incidents, these include: physical security and system security. In this research we focus on one of the elements of system security – authentication. We propose an interoperable Identity Authentication Framework for e-government. The research will adopt a qualitative case study and design science. This will be complemented with behavioural research approach. To achieve the main objectives, there are a number of activities planned for this research. These activities are: investigation of maturity level for e-government systems; assessing information security maturity level; evaluation of authentication systems in use; design the interoperable identity authentication framework; and evaluation of the proposed framework. The framework will go through a number iterations in design and evaluations.