Mitt Romney's campaign has zeroed in on Newt Gingrich's time advising mortgage giant Freddie Mac, hitting the former Speaker with a new television ad and a series of interviews with Romney and surrogates questioning the issue.

The campaign believes the former House Speaker's involvement with the organization many blame for helping to cause the housing crisis will be a particularly effective issue in Florida, one of the epicenters of the nation's mortgage collapse.

They've released a new TV ad capitalizing on that.

"While Florida families lost everything in the housing crisis, Newt Gingrich cashed in," said the ad's narrator. "Gingrich was paid over $1.6 million by the scandal-ridden agency that helped create the crisis."

Romney began this line of attack Saturday, telling The Hill and other reporters that "I'd like to see what he actually told Freddie Mac. Don't you think? This is a big issue. We've got a Washington insider talking about Freddie Mac. Let's see what his report was to Freddie Mac, what he said to them, what advice he gave them."

The argument was too little, too late for Romney in South Carolina — he ended up losing the state by a wide margin to Gingrich. But with 10 days until Florida's primary, all eyes are focused on its results. Whoever wins the state will likely emerge as the front-runner for the nomination.

Romney continued that attack on Fox News Monday morning.

"With Newt Gingrich, it's an October surprise every day," Romney said. "Let's make sure that we understand what was in the work product that he was providing to Freddie Mac. What was the contract, what did they pay him for? You don't pay someone $1.7 million just to write his history. Did he write their history? Let's see the work product. Did he lay out their history, or did he write policy and provide access to people in power?"

Gingrich has argued that he did not lobby for Freddie Mac, but acted as a "historian" for the mortgage giant.

Former Minnesota Gov. Tim Pawlenty (R), a top Romney surrogate, kept up the drumbeat later Monday morning, calling Gingrich a "lobbyist and influence peddler."

"To say that he wasn’t a lobbyist is incredible hair-splitting," said Pawlenty on conference call organized by the Romney campaign. "One of the most devastating blows to the Florida economy was the collapse to the housing market. The notion that he was paid $1.7 million as a historian for Freddie Mac is just BS, it’s just nonsense."

Watch the ad here: