"what is the prime minister's role?"

Thanks for your question about the Prime Minister. They have many roles, including:

• chairing meetings in which the government discusses policies and examines bills—proposed laws
• selecting members of the government to be ministers
• leading Cabinet (the Prime Minister and ministers) in deciding government policy
• acting as the chief government spokesperson
• representing the Australian Government overseas
• advising the Governor-General about important issues such as the appointment of ambassadors and heads of government departments
• advising the Governor-General about constitutional matters
• deciding when to call a federal election and leading the government in the election.