Commonwealth Bank of Australia has warned its staff the banking royal commission will this week hear evidence about its unfair behaviour toward some customers.

‘There will be cases highlighted next week where customers have been treated unfairly by us,’ incoming chief executive Matt Comyn said in an email to staff released to media outlets.

‘In many cases, our actions have had a significant impact on the financial and emotional wellbeing of our customers. This is unacceptable.’

The Royal Commission into Misconduct in the Banking, Superannuation and Financial Services Industry will resume in Melbourne on Monday to hear evidence from ANZ and CBA executives.