NEW YORK (Reuters) - Billionaire investor Warren Buffett said the US economy remains in recession, disputing this week's assessment by a leading arbiter of economic activity that the downturn ended more than a year ago.

"We're still in a recession," Buffett told CNBC television in an interview broadcast yesterday. "We're not gonna be out of it for a while, but we will get out."

On Monday, the National Bureau of Economic Research said the world's largest economy ended an 18-month recession in June 2009, but cautioned that its assessment did not mean normal activity had resumed.

Buffett said he defines a recession differently from the NBER, saying it ends when real per capita gross domestic product returns to its pre-downturn level.

Buffett, 80, runs Berkshire Hathaway Inc, which has roughly 80 operating businesses. "A great majority" of these businesses are "coming back slowly," he said.

Berkshire's operations cover a broad swath of the economy, including the Burlington Northern Santa Fe railroad, Dairy Queen ice cream, Geico auto insurance, and luxury jewellers such as Borsheim's.

Shipments at Burlington Northern are "61 percent of the way back", Buffett said. "Our carpet business, our brick business, our insulation business, they're not back 61 percent, but they are moving back."

On Tuesday, the US Federal Reserve, which has already driven short-term lending rates to near zero, said it is prepared to provide additional stimulus to support economic expansion and avert possible deflation.

"We've used up a lot of bullets," Buffett said. "And we talk about stimulus. But the truth is, we're running a federal deficit that's nine percent of GDP. That is stimulative as all get out."