The role of policy is to provide the framework for the direction of care at all levels - national, state and organisational. With implementation of strategic plans in many states and territories, nurses will often have responsibilities in relation to both regional and service planning.
Policy development is not a starting point but rather a response to a problem or opportunity of sufficient magnitude or urgency that a planned response is called for. 
There are many models of policy development to guide approaches, including the Policy Circle or Six Ps Model covering: 
- Problem (defined issue)
- People/places (stakeholders and site of action)
- Process (the act of policy development)
- Price tag (any cost implications)
- Policy document (proposed policy to address the problem)
- Program and performance (strategies to implement and monitor the policy).
In Australia this planned approach is important because state and federal parliaments share responsibility for health service delivery (federal for payments to doctors and medicines, and state and territory for hospitals). Even within a care setting there will be various stakeholders and cost implications that require a planned approach and consultation.
Some nurses work in policy and development roles. Others such as nurse managers will have aspects of this in their broader role. Most will not be involved in all aspects of policy planning but understanding the process helps to identify where contributions might be made.