The Fed has been terribly wrong about inflation and is going to have to 'bite the bullet' on rate hikes, says Wharton's Jeremy Siegel

• The Federal Reserve has been wrong about inflation, said Wharton professor Jeremy Siegel.
• "I'm actually disappointed that Chairman Powell did not look at the history that this is not a time for us to slow down," Siegel told CNBC.

The US Federal Reserve has made a series of policy blunders that have pushed inflation to historic levels, and now is not the time time to pull back on planned rate hikes, said Wharton finance professor Jeremy Siegel.

While chairman Jerome Powell indicated yesterday that the first rate hike in March will likely be 25 basis points, Siegel said the Fed's already behind, and should instead be making a more aggressive, half-point move this month.

"They're going to have to do much more than that," Siegel said in a CNBC interview. "I'm actually disappointed that Chairman Powell did not look at the history that this is not a time for us to slow down."

The Wharton professor also noted that he is disappointed that the Fed doesn't have a solidified plan to drain the balance sheet.

The Fed's already been behind on taming historic inflation, he added, which means it isn't time to ease the pace of interest rate hikes, even in the face of a new war in Europe following Russia's invasion of Ukraine.

He reiterated his opinion that the central bank should not let the Russia-Ukraine crisis impact their plans for monetary policy, as inflation is a pressing economic problem that needs to be addressed.

Similarly, legendary investor and Pimco cofounder Bill Gross said Thursday that the Federal Reserve is "stuck in a low interest rate world," and that he thinks a mild recession could be on the way — one that the Fed won't be able to prevent.

"Jay Powell's a very very good man but the Fed has been very wrong, and they're going to have to catch up, and they're going to have to…bite the bullet. We have to defend the dollar," Siegel said.