Millionaire businessman Dick Smith has slammed Australia's franking credits system after revealing he received $500,000 of the controversial rebates in a single year.

Mr Smith said he doesn't feel that it is right for someone of his wealth to receive a tax advantage and now he is asking Australian Tax Office how he can not receive the money anymore. 

Franking credits are a rebate to those whose share dividends have already been subjected to the company tax and can be used to reduce an individual's basic income tax liability, so they aren't taxed twice for the funds.