Are Australians losing their confidence in Australian banks that 1 million Aussies have moved out their accounts from these lenders in the past 12 months?

Of the 1 million, 855,000 people left their bank, 65,000 no longer deal with a credit union, 18,000 no longer does business with a building society and another 140,000 severed their relationship with other financial institutions.

The Roy Morgan Research Consumer Source Survey, released on Monday, identified ANZ Bank as the worst hit among the big 4 with 4 per cent of its customers leaving the lender.

ANZ Bank was followed by Westpac which lost 3 per cent of its customers, Commonwealth Bank, 2.7 per cent and National Australia Bank, 2.3 per cent.

Smaller banks also suffered from customer loss such as BankWest (5.6 per cent), ING Direct (5.2 per cent), St George (3.8 per cent) and Bendigo Bank (2.9 per cent).

"Our research shows the key reasons why people switched their main financial institutions include high fees and charges, poor service and poor interest rates," Roy Morgan Banking Industry Communications Director Norman Morris explained, quoted by Business Spectator.

The survey had more than 25,000 respondents and was held in a period of six months.

However, Mr Morris said that it is not only the banks that are affected by this development but also customers because they lost the opportunity to tap financial products of the lenders. In the case of those who left CBA, it involved 7.9 financial products, 8.7 products for ANZ ex-customers and 10.7 products for Bankwest clients.

Mr Morris urged the lenders to find out where have the customers shifted their business to for a better understanding of their move to cut business ties with a particular bank.