The general rule of thumb is that you should borrow in the same currency as the property you have purchased. If you don’t, you are exposed to currency risk and this could lead to your lender asking you to top up the security if the currency moves against you.
Borrowing against your Australian property portfolio to buy additional overseas properties is fraught with danger. If you are considering this approach, you should seek professional guidance before proceeding.
In most countries, there are restrictions on the amount a foreign investor can borrow from a local financial institution. In some countries the borrowings may be limited to 60%, 50% or even less. You should consider how you are going to finance a property before you commit to purchasing the property.