Billionaire investor Warren Buffett is calling on his "mega-rich" friends to pay more in taxes, saying they've been protected too long from the government.

"My friends and I have been coddled long enough by a billionaire-friendly Congress," Buffett wrote in an op-ed piece in the New York Times. "It's time for our government to get serious about shared sacrifice."

Buffett said investment managers like himself can classify their income as carried interest, meaning they pay only a 15-per-cent tax rate.

"These and other blessings are showered upon us by legislators in Washington who feel compelled to protect us, much as if we were spotted owls or some other endangered species. It’s nice to have friends in high places," he wrote.

He said the mega-rich pay income taxes at a rate of 15 per cent on most of their earnings but pay practically nothing in payroll taxes. But he said the middle class pay somewhere in between 15 per cent and 25 per cent and also pay heavy payroll taxes.

Buffett said tax rates should be raised for those making more than $1 million and an additional increase for those who make $10 million or more.

"Most wouldn’t mind being told to pay more in taxes as well, particularly when so many of their fellow citizens are truly suffering," Buffett said.