The housing market is headed for another downturn, as government assistance comes to an end, star bank analyst Meredith Whitney says.

She also says that mortgage-backed securities and Treasuries are headed for the skids. “The housing market surely will double dip," Whitney said.

Government programs to support the market have produced mixed results. And when mortgage-modification efforts end, the home-supply overhang will worsen, she recently told CNBC.

As for mortgage-backed securities (MBS) and Treasuries, they’re overbought, Whitney maintains.

"The asset classes of MBS and Treasuries are priced for a material correction," she said.

"The only buyers of agency MBS are the Fed and banks, so you see how precarious that market is. If the Fed pulls back, that's a really big deal ... because there's no substitute buyer."

Whitney doesn’t think banks are going to open their lending spigot anytime soon.

"I don't think there's much the Fed can do to get banks to start lending again,” she said. “That's a structural problem, the model is broken.”

Banks don’t want to hold any mortgages that they issue, she says. “They're issuing everything to dump on (Fannie Mae, Freddie Mac and Ginnie Mae).”

Not everyone is so pessimistic about home prices. Recent data are positive, says Millan Mulraine, of TED Securities.

"We may only be a few months away before we see a monthly gain in national home prices," he wrote to clients.