Monday marked the beginning of candidate qualifying week in Florida, but the battle in the 25th district is already raging.

Most of the early fire is being directed at state Rep. David Rivera (R), who has jumped out to a large fundraising lead in the early stages of the race to replace Rep. Mario Diaz-Balart (R).

Rivera entered the race soon after Diaz-Balart announced in February that he would run for the 21st district seat that his brother, Rep. Lincoln Diaz-Balart (R), is retiring from at the end of this term. Rivera raised more than $700,000 for his campaign in a little over a month, according to his first Federal Election Commission report.

He was set to add a good amount to that total Monday evening when more than 30 House Republicans, including most of the party’s top leaders, held a fundraiser for his campaign on Capitol Hill.

But Rivera’s opponents are working to turn his early fundraising advantage into a liability.

Former Miami-Dade County Democratic Party Chairman Joe Garcia — the likely Democratic nominee who came 6 points shy of beating Mario Diaz-Balart in 2008 — criticized Rivera late last week in a Miami newspaper for raising money from lobbyists for his federal campaign while the state Legislature was in session. Garcia, who entered the race two weeks ago after being heavily recruited by state and national party officials, said Rivera’s fundraising efforts during the state House session violated the spirit of Florida campaign finance laws.

Then, on Monday, one of Rivera’s primary opponents said it was unseemly for Rivera to be in Washington, D.C., raising money from national party bigwigs on the first day of qualifying in the state.

“I find that improper considering that today is the first day that one can officially [qualify] for the race,” attorney Marili Cancio said.

Cancio also criticized national party officials for getting involved in the Sunshine State primary.

“Obviously, by hosting the fundraiser today, they are proving who they want,” Cancio said.

Rivera was named to the National Republican Congressional Committee’s “Young Guns” campaign fundraising and infrastructure program earlier this month and has quickly moved up to its second-highest tier.

Cancio said she was invited to join Young Guns, too, but declined.

“I said, ‘How many Young Guns can you have in one race?'” she said.

Rivera’s campaign spokeswoman, Leslie Veiga, chose not to respond to Cancio on Monday, but she did criticize Garcia for beginning his campaign with an attack.

“We’re trying to run a campaign based on issues,” Veiga said. Garcia is “going after [Rivera] for somewhat frivolous things.”

Veiga said she expects that Garcia is attacking Rivera early in the race because he knows he’s behind.

But one poll shows the race to be a statistical dead heat.

According to a survey that was commissioned by the Democratic Congressional Campaign Committee late last month, Garcia led Rivera 38 percent to 35 percent, with 24 percent undecided.

That 3-point lead was within the survey’s 4.8-point margin of error. The poll found that independents broke for Garcia by 26 points.

The survey of 417 likely general election voters was conducted by the Benenson Strategy Group for the DCCC March 24-27.

The poll was commissioned by the DCCC in part to persuade Garcia, who had taken a job with the Obama administration after his 2008 campaign, to throw his hat back into the ring. With Garcia in the race, Democrats hope that the 25th district will be one of the few places the party can play offense in a cycle where it is very much on defense.

Last cycle, Garcia proved a prolific fundraiser, eventually raising about $1.8 million after entering the contest in February 2008.

This time around, Garcia is using the same finance director but is using a new pollster, communications firm and general consultant. Pete Brodnitz of Benenson Strategy Group has been hired to do Garcia’s polling.