Traditional institutes like banking had fraud and security controls built for a time where batch processing was prevalent. With the shift towards near-instant payments, fraud detection and security controls need to adapt accordingly. It is no longer sufficient to monitor logs, or track suspicious activity 12 or 24 hours after the fact - rather systems need to be designed in a streamlined manner with security and fraud controls that can detect threats rapidly so that appropriate counter-measures may be taken.
Currently, when money is transferred it gets lodged in batches that go through a clearing house, with the big four banks in Australia running their own batch clearing practice; there is also a collection of second-tier clearing houses that perform transaction clearing. These transactions are held for a number of hours to allow batch analytics to be run thoroughly and for time to isolate dodgy transactions.