Some Republicans are raising concerns ahead of a key special election in Florida on Tuesday in what appeared to be a safe U.S. House district for the party as Republican state Sen. Randy Fine vies for the chance to take the seat vacated by former Rep. Mike Waltz.

The special election in Florida’s 6th Congressional District, which is on the state’s eastern coast and includes the city of Daytona Beach, is being held on Tuesday, April 1, to fill the vacancy created by Waltz when he resigned to become President Donald Trump’s national security adviser.

Another special election, in the state’s 1st District, will also occur on April 1 to fill the vacancy left by former Rep. Matt Gaetz when he resigned from Congress late last year.

While Republicans are favored to win both races, given that the districts were ruby-red in 2024, some have speculated that the margin between the Republican and Democratic candidates could be tighter than anticipated, given Trump’s voter disapproval ratings and Democrats’ success in some recent legislative district elections.

With Fine specifically, some Republicans have raised concerns over his fundraising and campaigning.

Fine’s fundraising has lagged behind Democratic candidate Josh Weil, according to filings with the Federal Election Commission. Fine has raised or received about $987,000 from late November 2024 through mid-March, while Weil has raised or received over $9 million from Oct. 1, 2024, through mid-March. Fine also donated $600,000 to himself last week, according to other FEC filings.

(Weil’s campaign has spent over $8 million of its money, per the filings. Fine’s campaign also spent much of its money before his own donations last week.)

Those voicing concerns about the race include some Republicans. Florida Gov. Ron DeSantis, for instance, told reporters on Tuesday, “Regardless of the outcome in that, it’s going to be a way underperformance from when I won that district by in ’22 [as a candidate for governor] and what President Trump won in November.”

“They’re going to try to lay that at the feet of President Trump,” DeSantis added. “That is not a reflection of President Trump. It’s a reflection of the specific candidate running in that race. And President Trump, if he were on the ballot in this special election, he would win by 30 points, no question.”

DeSantis did say that he still expects a Republican candidate will be successful in the district. Still, DeSantis and Fine have clashed before, including when Fine switched his endorsement in the 2024 presidential primaries from DeSantis to Trump.

Steve Bannon, a former Trump adviser, said on Monday on his podcast show that “Trump won that district by 30 points in November. … We have a candidate that I don’t think is winning. That’s an issue.”

ABC News reached out to Fine’s campaign for comment about the Republican concerns.

Fine, on social media, has continued to express optimism, writing on X on Tuesday night, “As I sit in my [state] Senate office for the last time, I want to thank the voters who have elected me seven times to represent them in Tallahassee. It’s been a profound honor, and I can’t wait to do it again.”

The National Republican Congressional Committee, the campaign arm of House Republicans, has not invested in the race but indicated it is not worried about a loss.

“Randy Fine is going to be a member of Congress. Everything else is just noise,” Mike Marinella, a spokesman for the NRCC, told ABC News.

Fine, who was elected to the Florida state Senate in 2024, previously served as a state House representative and worked beforehand as a casino executive. In the state legislature, Fine promoted bills on school choice, immigration, combating antisemitism and other issues.

He also sponsored a high-profile measure in 2022 that would eliminate some special districts in Florida, including one that encompasses Walt Disney World, amid a fight between the Florida government and The Walt Disney Company. (ABC News is owned by The Walt Disney Company, which also owns Walt Disney World.) A settlement was reached in March 2024.

The Florida special elections could affect the balance of power in the House of Representatives. As of Wednesday, less than a week out to the special election, Republicans have a razor-thin majority in the U.S. House, with 218 seats to Democrats’ 213 seats. (Four seats, including the two Florida seats, are vacant.)

Fine does have some momentum — for instance, he does have Trump’s strong endorsement.

Trump wrote in late March on his social media platform Truth Social, “A highly successful, Harvard educated businessman, and greatly respected State Legislator, Randy has been a tremendous Voice for MAGA.” The president also encouraged Republicans to vote early. The early voting period began on March 22.

Fine also has recent history pointing in favor of Republicans holding on to the district.

In the U.S. House general election in this district in 2024, Waltz received 67% of the vote, while Democratic candidate James Stockton received 33% of the vote. In this district in the presidential race, meanwhile, Trump received about 65% of the vote, while Vice President Kamala Harris received about 35% of the vote.

Both Democrats and Republicans have said special elections are not necessarily comparable to regular elections, given that voter turnout can be much lower during the special elections.

ABC News’ Lauren Peller and Soo Rin Kim contributed to this report.