ABC News' Michael Falcone reports:

JACKSONVILLE, Fla. - Newt Gingrich is not just getting outspent by Mitt Romney and his allies on the Florida airwaves, he's getting creamed.

The Romney campaign and a super PAC supporting him is spending nearly quadruple the amount that Gingrich and the pro-Gingrich super PAC, Winning Our Future, has spent to air television and radio ads ahead of the state's Jan. 31 primary.

So far, Romney has bought $5.6 million worth of airtime and the pro-Romney super PAC, Restore Our Future, has shelled out a whopping $8.2 million, according to a Republican media buyer who is tracking ad spending in the state.

Compare that to $837,000 spent by the Gingrich campaign and the nearly $3 million of airtime bought by Winning Our Future, a super PAC supporting the former House speaker, and it's easy to understand one reason why Gingrich has slipped in the most recent polls in the Sunshine State.

Pro-Romney forces are using the vast majority of the $13.9 million they've spent to buy up television airtime on broadcast stations in the Miami, Tampa and Orlando areas  - population centers that will be critical to the former Massachusetts governor's hopes of winning the state.

Gingrich is following a similar pattern, and Winning Our Future is also spending more than $1 million on radio ads. Cumulatively his campaign and the super PAC supporting him has purchased roughly $3.8 million of television and radio time.

These figures, which represent money that has already been spent in the Sunshine State, are approaching $20 million and the political ad spending is on pace to surpass  that before next Tuesday.

Earlier this week, Winning Our Future was touting a fresh $5 million infusion of cash from the wife of the Las Vegas billionaire Sheldon Adelson, but so far, the group has only spent a fraction of that total. Rick Tyler, a spokesman for the PAC, has pledged to buy up at least $6 million worth of airtime before voters go to the polls next Tuesday.

With less than four full days of campaigning left before the primary, Gingrich's campaign unveiled a new ad on Friday accusing Romney of attempting to "mislead, distort and deceive just to win an election."

At least one other group is play the anti-Romney game in Florida. The left-leaning labor union, AFSCME, has spent nearly $1 million on television ads hitting Romney, who is leading in the most recent polls in Florida.