ABC News' Michael Falcone reports:

GREENVILLE, S.C. - Super PACs have emerged as the big-money behemoths of the 2012 campaign, and in the closing week before the South Carolina primary, new figures show that the groups have far outspent the candidates they are supporting.

The super PACs, which are allowed to raise unlimited sums but cannot coordinate with candidates, have spent over $7 million so far in the Palmetto State compared to all of the presidential contenders, who have spent a combined total of $3.2 million. In other words, super PACs have spent $3.8 million more on television ads in the state than the candidates, according to a source tracking media buys in early primary states.

Groups like the pro-Romney Restore Our Future PAC and the pro-Santorum Red, White And Blue Fund are making their presence known on the airwaves in the final days before voters in this important early nominating state go to the polls on Jan. 21.

Restore Our Future, which has been running negative ads against Newt Gingrich, unleashed a new one on Friday accusing Rick Santorum of supporting wasteful government spending and voting to raise the debt limit. The PAC has spent a total of $2.1 million in the state so far.

The Red White And Blue Fund, which is backing Santorum, recently placed a $603,000 ad buy on broadcast television in South Carolina. They are airing a new ad called "Pride" which offers a positive view of the former Pennsylvania senator. The group has spent roughly $767,000 to date here.

A pro-Perry group, Make Us Great Again, has spent $1.9 million in the state and added $150,00 to its television buy starting on Saturday and continuing until the primary. A pro-Ron Paul group, the Santa Rita PAC, has spent $325,000 in South Carolina and a pro-Jon Huntsman group, Our Destiny PAC, spent $50,000.

Another pro-Romney group, Citizens For a Working America, went up this week with their first ad buy in the state, spending $235,000 on air time between Thursday and next Saturday.

Compare those totals to what the candidates have been spending in the state and it's easy to see why super PACs loom so large over the presidential campaign:

Mitt Romney: $1.1 million

Ron Paul: $880,000 (Note: Paul purchased $412,000 of air time on broadcast stations and cable in South Carolina from Friday through Jan. 21)

Rick Perry: $592,000

Rick Santorum: $434,000

Newt Gingrich: $238,000

The power that super PACs wield has come under more intense criticism in recent days. Sen. John McCain predicted, in an interview with ABC News, that the groups will "destroy the political process." And Comedy Central host Stephen Colbert has launched a tongue-in-cheek presidential bid designed, in part, to stir up discussion about the outsize influence of super PACs.