If you want to work in a large public hospital they prefer you to have completed a grad program but its not essential. Most private hospitals you don't need a grad program.
You must remember that to be refered to a bridging program you must have at least a 7 for all parts of the English test, you need to have done a bachelor degree in your home country and have at least 2 years full time equivalent working as a nurse in your home country for Ahpra to approve you for a bp