The function of the treasury department in a government involves managing the country's finances, including revenue collection, debt issuance, and economic policy formulation. It is responsible for overseeing monetary resources, implementing fiscal policies, and promoting economic stability. The treasury department prepares annual budgets, manages government expenditure, and coordinates with the central bank to regulate monetary policy. By maintaining financial integrity and stimulating economic growth, the treasury department plays a critical role in a nation's financial health and governance.