Stamp duty is a “State based” tax levied on certain transactions, including the purchase of real estate. The rate you’ll pay varies in each state and territory.
As stamp duty is a tax, you cannot borrow money to cover it, though it can accommodated for by reducing the amount of your cash deposit and increasing your home loan to cover the difference. This may mean taking out lender’s mortgage insurance (LMI) [What is Lender’s Mortgage Insurance?] to compensate for your reduced deposit.