National Australia Bank is still sorting through a backlog of transactions after restoring its mobile internet banking and call centre services following system outages.
NAB's chief consumer officer Andrew Hagger said many customers were now able to log onto NAB Connect, NAB internet banking and UBank online banking.
"We have also now processed a large number of overnight transactions which had been delayed," he said in a statement.
"However, I understand there are still customers waiting for payments - this delay is not acceptable and we apologise."
He said the bank was working as quickly as possible and customers should feel reassured that their money is safe.
Customers can still use NAB ATMs and debit and credit cards.
The bank is still investigating the cause of the system outage.