The bank has pledged to devote 30% of its annual budget, estimated to be between A$1.8bn to A$2bn, for the next four years to upgrading its tech.

The move is part of Project Unite, 85 separate tech projects designed to reverse a decade of under-investment.

The main purpose of the project is to reduce duplication and cut the number of systems by two-thirds, from 180 to 60.

"We have more technology than we need," said Westpac chief executive Peter King in comments reported in the Australian media.

King also said that the timing of the upgrade was optimal because the bank had completed the sale of its non-core businesses as well as a lengthy risk management upgrade.

And while the bank had been working on a technology simplification programme for many years, the latest announcement represents a significant accelerration of these efforts.

According to the bank’s chief information officer Scott Collary, a number of projects have already been completed including the reduction of customer onboarding systems and consolidating communication networks.

The main focus for the bank in 2024 will be on "improving customer outcomes", simplifying things for bankers and reducing costs, rather than the replacement of core banking systems, said Collary.

“Core systems are not big drivers of these issues. The core will be addressed at the end of this.”