Australia's "appalling and greedy" super-wealthy people have come under fire for refusing to donate 20 per cent of their income to charity this Christmas.

Bank bosses have particularly raised the ire of businessman Dick Smith, who two weeks ago wrote to the chief executives of the nation's Big Four financial institutions urging them to give away a fifth of their income.

Dick Smith ... says he gives more than 20 per cent of his income to charity.

As of this morning none had pledged their support.

Only Commonwealth CEO Sir Ralph Norris wrote back, telling the electronics baron he gives to charity privately.