Yes, Australian bank accounts are frozen when someone dies. If you want to close the account of somebody who has died, you might have to provide proof of death and a copy of the will. You might also have to prove your relationship to the deceased person.
If you have a joint bank account with somebody who has died, you will generally be entitled to all the money in the account. Again, you might have to provide proof of death if you want to change the bank account from a joint account to a one-person account.