Billionaire investor Leon Cooperman slammed Democratic presidential candidates Elizabeth Warren and Bernie Sanders on their proposals to put an additional tax on the richest Americans.

"Stop portraying billionaires as criminals," Cooperman said Wednesday on CNBC, the morning after Warren and Sanders in the latest Democratic debate cast themselves as the hard-liners on tacking wealth inequality.

"They make it sound like rich people don't pay taxes," the Omega Advisors founder said on "Squawk Box."

Warren's plan calls for a 2% tax on families' net worth of more than $50 million, which she has turned into a rallying cry for the rich to pitch in 2 cents for every dollar above that threshold.

"You make it to the top, the top one-tenth of 1%, then pitch in 2 cents so every other kid in America has a chance to make it," Warren said at Tuesday night's debate in Ohio.

The Massachusetts senator also wants to put a 3% tax on household net worth over $1 billion.

The wealth tax from Sanders, a Vermont democratic socialist, would be progressive, starting at 1% for household net worth of more than $32 million and ending at 8% on wealth over $10 billion.

Cooperman said he would rather see the government look into raising the federal income tax rate or the capital gains tax rate — paid by people who buy or sell assets, like stocks or homes.

"I believe in a progressive income tax structure. I believe rich people should pay more. I have no problem with that. This wealth tax is baloney," he added.

Paraphrasing late British Prime Minister Winston Churchill, Cooperman said that "you don't make poor people rich by making rich people poor."

Cooperman is not alone among wealthy Americans who believe rich people should be taxed more.

Billionaires Warren Buffett and Bill Gates have also said for a long time that taxes should go up on the wealthy. But they, too, believe there are better ways to make the tax system more fair than a wealth tax.

CNBC has reached out to the Warren and Sanders campaigns for comment.