Despite recent signs of weakness, the US economy is unlikely to slip back into a recession, says Warren Buffett.

Speaking at the 25th anniversary dinner of the Economic Club of Washington on Tuesday, the billionaire investor said he saw the odds of a renewed recession as "very low".

But he warned that could change if the effects of Europe's financial crisis were to "spill over in a big way".

European leaders need to reconcile the "half-in, half-out" nature of the eurozone, Buffett said. The 17 nations that use the euro share the same central bank and interest rate policies, but follow wildly different national tax and budget policies.

Buffett, who is the chief executive of Berkshire Hathaway, based in Omaha, Nebraska, also reaffirmed his support for the so-called Buffett rule. The proposal would require Americans with incomes above $1m to pay a 30% tax rate.

"I couldn't get a disease named after me, so I settled for a tax," he said.

When asked how he would reduce the US government's budget deficit, which is on track to top $1tn for the fourth year in a row, Buffett recommended raising taxes and cutting spending.

"The problem is the Democrats don't want to talk about what expenditures they would cut and the Republicans don't want to talk about raising revenues," he said.

"You've got to get specific about it," he added. "Just talking about reform won't work."

That echoed the criticism many Democrats have levelled against the Republican presidential nominee, Mitt Romney. They say his budget-cutting proposals consist mainly of broad targets and do not include enough details about actual cuts.

Buffett jumped into the tax debate last August by noting that he pays a lower tax rate than his secretary, which he said was unfair. Like many wealthy Americans, much of Buffett's income comes in the form of capital gains and dividends, which are taxed at lower rates than incomes.

President Barack Obama and Democrats in Congress seized on Buffett's approach. But it has failed to gain much traction in Congress. A proposal modelled on the Buffett rule was defeated in April in the Senate. It fell short of the 60 votes needed to cut off Republican legislative manoeuvres to block a final vote.