(Bloomberg News) Warren Buffett, the billionaire investor, said the ability of some of the highest earners to avoid federal taxes shows why laws should be changed so the wealthy pay more.

“They were the moochers, and they paid zero,” Buffett, the chairman of Berkshire Hathaway Inc., said today in an interview on MSNBC. “The way they get at them is a minimum tax and it’s very simple to do.”

Buffett is pressing his call for a minimum tax on incomes above $1 million as lawmakers seek to avoid the so-called fiscal cliff, which would impose more than $600 billion in tax increases and spending cuts starting in January. He said in a New York Times opinion piece yesterday that higher taxes on the wealthy won’t thwart investment.

Buffett’s remarks contrast with the position of Mitt Romney, the defeated Republican presidential candidate, who said in comments broadcast on CBS’s “60 Minutes” in September that low rates are “the right way to encourage economic growth, to get people to invest.” Romney, speaking to campaign donors at a private fundraiser in May, said Democratic President Barack Obama’s support came from the 47 percent of Americans who see themselves as “victims,” dependent on government.

Buffett said today that among the 400 with the highest incomes in the U.S. in 2009, the average income was about $200 million, and that six people in that group paid “nothing at all.”

“They were in Romney’s 47 percent,” Buffett said.

Buffett’s tax bill for 2010 was about $6.9 million, or 17 percent of taxable income, he wrote in the Times last year. He said that’s a lower rate than the other 20 employees in Berkshire’s office in Omaha, Nebraska, and that the wealthy benefit from favorable treatment of capital gains and dividends, compared with wages. Buffett’s salary is $100,000 a year.