Westpac Bank says that about 10,000 customers have been affected by a technical glitch that has held up salary and other payments.
The bank says government employees are among those who did not receive their pay overnight for that reason.
It says all payments will be in bank accounts by the end of Wednesday, and many by the afternoon.
Westpac has apologised for the glitch, promising that no one will be penalised as a result of it. It says it is investigating how it happened.