Gabriel E. Gomez, a former Navy SEAL and private equity investor, took out nomination papers Monday to run as a Republican in the special election to replace Senator John F. Kerry, according to the office of Secretary of State William F. Galvin.

The move paves the way for Gomez to formally kick off his campaign, and sets up a contested Republican primary, pitting Gomez against State Representative Daniel B. Winslow, a former aide to Governor Mitt Romney.

Gomez had previously said he was likely to run and party insiders have been preparing for his entry into the race, following the decision by better-known figures, such as former senator Scott Brown, to stay out of the race.

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Gomez, who is unknown but quietly gathering support from top Republicans, will now have until Feb. 27 to collect 10,000 certified signatures from voters to qualify for the April 30 primary.

Neither Gomez nor his advisors returned phone calls Monday afternoon seeking comment.

Gomez is in the process of hiring a major firm to gather his signatures, SpoonWorks Inc., at a cost of more than $100,000, according to a top GOP official who has been consulting with Gomez. Harold Hubschman, owner of the company, would not comment, saying he does not discuss his clients publicly.

There is concern among Republicans that the short window for gathering signatures, amid rough weather, could jeopardize the party’s chances of fielding a candidate.

Hubschman, who has been paid more than $2.5 million over the last decade on petition drives for state races and referendums according to state campaign finance records, said it can be done.

“We know we can do it. It’s not impossible,” Hubschman said. “It’s just very difficult.”

State Senate minority leader Bruce Tarr, of Gloucester, is also weighing a run.

The top Democratic candidates are both US Representatives, Edward J. Markey of Malden and Stephen F. Lynch of South Boston.