National security should supersede privacy concerns in major issues, Warren Buffett said on CNBC Monday, weighing in on Apple's fight against a government order to help hack the iPhone of one of the San Bernardino terrorists.

"We live in a very, very, very dangerous world," he said. "If you were in the early days of September 2001 and you were receiving credible information that something was going to happen ... I think that in that case security trumps privacy."

But in what Buffett calls "fishing around on smaller-type things," he'd side on the side of privacy.

"If there's something major, something that the attorney general or the head of the FBI would be willing to sign, and go to a judge on, and say, 'We need this information and we need it now,' I would be willing to trust that official to behave in a proper matter," Buffett said.

"Privacy has its limits," Berkshire Hathaway's chairman and CEO told "Squawk Box," two days after releasing his annual letter. He said he's not taking sides in the Apple versus FBI battle.

Buffett said he understands the position of Apple CEO Tim Cook, who does not want to open up the iPhones of everyday Americans to government scrutiny.

"I don't know Tim [Cook] real well. Everything I know about his is he's a high-grade an individual as you can imagine," he said.

"I think, frankly, Apple would cooperate if it was a targeted sort of thing where they felt it was very important to national security. But I don't think they want to unlock millions of phones," he added. "You can't call everything national security."

Buffett said Berkshire has been asked to help the government on occasion. While he would not elaborate, he did say many businesses are asked to cooperate with the government.

If Berkshire were to be asked to manufacture something key to national security, he said the company would try to do it. That's been part of Apple's argument — saying the government is asking the tech giant to write code, in essence, make something that doesn't exist.

"I expect my bank to cooperate with the United States government. I expect my telephone company to cooperate," he said, within reason he offered as a caveat.

"If, at our railroad, we found mysterious shipments or something going on," he continued, "I would hope we would make sure the proper people in government knew about it."