A term deposit is a contract to leave a fixed sum with a bank for a fixed period at a fixed rate. The bank prices it on the assumption the money stays put, which is why it can offer certainty a savings account cannot. Withdrawing before maturity breaks that contract, and every provider sets terms for doing so.
The first of those terms is notice. Most Australian banks require up to 31 days’ notice of an early withdrawal, and that clock starts when you lodge the request, not when you first ring up. Some providers release funds faster at their discretion, and some do not. Treating a term deposit as an emergency fund is where this catches people out most often, because in a genuine emergency the money may be a month away.
The notice requirement is generally waived in cases of demonstrated financial hardship, and providers also make exceptions for events such as the death of an account holder. Hardship is assessed case by case, so it is a safety valve rather than an option you can plan around.