Image: Westpac

The bank makes the claim in a video emailed to home loan customers on Monday night.

The video is narrated like a children's bedtime story, even beginning with the words: "Once upon a time …"

It then moves on to explain the story of how banana crops became more expensive following Cyclone Larry, and likens that event to what the bank weathered during the great financial crisis.

The animation - which shows a 50 cent rise in smoothies and then bags of money being poured into a bank - has been described as condescending by marketing experts.

"The story book approach doesn't really help people understand what's going on," Deakin University's Dr Paul Harrison told the ABC.

"From my perspective, it actually looks condescending and patronising, and probably for most of the consumers who are living with the rate rise, it will feel that way as well."

An MSN forum user pointed out that the analogy to banana smoothies isn't correct, as people can choose to pay more for a smoothie but are tied to their mortgages.

Neither Westpace retail chief, Peter Hanlon (the man who sent out the video), nor chief executive, Gail Kelly, were available for comment.

A Westpac spokeswoman did comment that the bank had honourable intentions by simplifying the issue.