Investor Warren is critical of the US government's "stress tests" of US banks, saying they do not properly assess the industry's health.
His Berkshire Hathaway company holds stakes in three banks that underwent the tests, Wells Fargo, US Bancorp and SunTrust Banks.
Mr Buffett said the tests ignored differences in business models, but added it was right the government try to save banks.
The BBC reports that results of the stress tests were due to be published on Monday, but have been delayed until Thursday.
Mr Buffett was speaking at a news conference with Berkshire Hathaway vice-chairman Charlie Munger, who said the 'one size fits all' reasoning was "very likely to be done poorly."
However Mr Buffett, who is the world's second-richest man, endorsed government efforts to stabilise the financial system and criticised the strategy of companies buying back their own shares.