Catherine Wolthuizen, the senior finance policy officer at the Australian Consumers Association, certainly thinks so: see the article at http://www.smh.com.au/news/Banking/Penalty-fees-leave-you-feeling-unbalanced-Bank-on-these-terms/2005/01/23/1106415453880.html

When I was charged by Amex for late payment I rang them and said I had not received the previous months invoice. They immediately said no worries and gave me a credit for that amount.

I remember thinking ..that was a bit too easy, but I got the credit as promised. I also found the invoice later under all the junk on my desk.

Perhaps they know they have no right to the money and simply take it from those who do not complain.

I had overpaid my credit card by a few dollars, so I transferred the money back to my savings account bringing the balance back to nil, via the internet. The bank charged me $2.50 for that privilege. I didn't pay that trivial amount, and waited till there was a bit more on the credit card, and so a $25 late payment fee was slapped on as well. Needless to say, I have cancelled the card and am happily using (to date) another user friendly one.
I can't be bothered with the greed of banks any more, and complaining seems to fall on deaf ears. I shall chop and change now and will not be loyal any more. Trouble is I get the feeling that they don't really care.

The same Contract principles outlined in the link apply in Aus - that a penalty clause for breach of a contract is unenforceable.
But whether there is statute that overrides this common law rule in this situation is something I'm unaware of.

What about the nice little money-spinner that Telstra has? By the time the bill arrives, you usually have 10-12 days to cough up or cop an $11.00 fine. I've been cheerfully deducting that amount from my bill for years. They'll have to try & collect it from my estate (hopefully way out in the future). Is this one illegal too? They are the only creditor other than the mankey banks that is arrogant enough to charge a late fee.

I had a credit card, but got rid of it when I switched banks. I wanted a savings account and to mainly deposit money and withdraw small amounts of cash when necessary, but due to charges I was losing more then I was putting in. Blow that for a joke. Banks are only good if you have large amount of cash. Banks think they can charge what they like. Well they can think again. I've now moved to a credit union account with less charges and I'm also now ING.

I get annoyed when I call up the Amex service centre an they transfer me to an Indian service centre and they can't speak basic English waste my time to re-phrase my question and repeat my reply.