The Commonwealth Bank took another digital step on Thursday launching a new way to withdraw money from ATMs: with a smartphone.

The bank’s 2.3 million app customers will be able to withdraw up to $200 once a day from any of 3000 ATMs without resorting to their plastic bank cards. Customers can also authorise someone to withdraw cash on their behalf by sending them a text message and PIN.

The new 'cardless' ATM

Using the app on an Apple iOS or Android device, customers can request the amount they wish to withdraw, then input two number codes - one from the app and one received in a text message - to withdraw money. It will be rolled out in May.

Michael Harte, the bank's chief information officer, said the idea for cardless withdrawals grew from an internal start-up competition in which the bank spent $10,000 to $100,000 on staff projects to rapidly build business cases.