President Obama has advocated what he calls the "Buffett rule," that the very rich should pay at least as high a rate as those with less money. Buffett publicly stated that he pays at a lower rate than his secretary and urged higher taxes on the "mega-rich."
Republicans argue Buffett should be open about his own taxes if he is going to advocate tax policy, The Hill reported.
"If he's going to be the gold standard, so to speak, in terms of what our tax policy should be, yeah, let's look at it," Sen. John Cornyn, R-Texas, said in an interview with ABC News.
Rep. Tim Huelskamp, R-Kansas, wrote an open letter to Buffett Thursday.
"Given the use of your name and your story as the guiding force for the president's policy prescription, it is my hope that the evidence to justify such a change in policy will soon be available for public review," he said.
Notable deaths of 2014 [PHOTOS]