Hi there @Rossella52,
The legal personal representative of the estate is responsible for managing these obligations. However, you as a beneficiary aren't personally liable for tax debts that existed before the person died, unless you're also the executor or administrator of the estate.
The bank's request to withhold funds until taxes are paid is unusual. Australian banks don't typically hold estate funds based on ATO tax debts in this way. If there's a genuine ATO debt, we'd normally work directly with the authorised legal personal representative to resolve it.
If you're the executor or administrator of the estate, you can notify us of the death and access the deceased person's tax records by completing our deceased estates notification process.