If Minneapolis Fed President Neel Kashkari gets his way, the nation's biggest banks will need to keep more cash on hand — a lot more.

The central bank branch has been studying the issue of how to prevent situations like the one that led to the financial crisis in 2008, and Kashkari said it is nearly ready to release recommendations it has gleaned from multiple public symposiums.

"Basically we need to double the capital requirement of the biggest dozen banks in America," he said during a question-and-answer session Tuesday.

Kashkari said the Minneapolis Fed is "about to release the final versions of our plan," and he acknowledged that the position he has been taking about big banks has not been popular.

"Some have expelled me," he said of friends in the banking industry. "Some of my good friends are really angry that I came out and said the biggest banks are too big to fail."

Indeed, the former Pimco executive, Treasury official and Republican California gubernatorial candidate has been railing against the financial industry's titans for years. He has charged that conditions exist that still could cause another crisis despite the myriad additional regulatory burdens put on banks in the past seven years.

For instance, he has taken on Jamie Dimon after the J.P. Morgan Chase CEO said the problem of too big to fail had been solved.

Kashkari said banks should have to follow capital rules similar to those imposed on ordinary borrowers who have to pay a 20 percent deposit when buying homes.

"If we made banks put 20 percent down in terms of equity on their own portfolio, we would basically protect taxpayers against future bailouts. Right now they have about half the equity they need," he said. "We can't control everything, but if we can identify the risks, do the analysis, put forward sensible solutions, then other legislators and policymakers can take it forward."