WASHINGTON — For the business group from Utah, the lobbying blitz started well before their plane touched down in the nation’s capital.

Heading to Washington to spend Tuesday urging House Republicans to take up a broad immigration overhaul, the team of Utah business leaders buttonholed several members of their state’s congressional delegation — Senators Orrin Hatch and Mike Lee, both Republicans, and Representatives Jim Matheson, a Democrat, and Chris Stewart, a Republican — as the lawmakers waited to board their flight Monday at the Salt Lake City airport.

“Our plea is to act now, do it now, lead,” Stan Lockhart, a former chairman of the Utah Republican Party, said Tuesday in an interview as he explained the group’s basic pitch. “Ask House leadership to lead, and let’s pass what’s possible now.”

Randy Parker, chief executive of the Utah Farm Bureau Federation, chimed in: “They need to act now. That’s the bottom line.”

Mr. Lockhart and Mr. Parker are part of an unlikely coalition of business executives, evangelical groups and prominent conservatives coming together to urge House Republicans to put broad immigration legislation on the House floor, ideally before the end of this year.

On Tuesday, the group of more than 600 leaders from roughly 40 states descended on the Capitol for meetings with nearly 150 Republican lawmakers. They are largely taking aim at House Republicans who they think could support a broad immigration overhaul, including some sort of legal status for the 11 million immigrants in the country illegally. The leaders are urging the lawmakers to take a more proactive role in pushing immigration legislation to a House vote.

“Our fly-in today is about moving votes on the Hill in support of reasonable immigration reform,” Randel K. Johnson, the U.S. Chamber of Commerce’s senior vice president for immigration and labor issues, said in a conference call with reporters. “I’m confident we’re going to move the ball forward.”

The event’s sponsors include the Chamber of Commerce; FWD.us, a political action group founded by Mark Zuckerberg, the creator of Facebook; the National Immigration Forum; and the Partnership for a New American Economy, which is led by Mayor Michael R. Bloomberg of New York, Rupert Murdoch and Bill Marriott Jr.

The effort kicked off in the morning with several panel discussions at the Chamber of Commerce, including one conversation in which the Bipartisan Policy Center, a nonprofit based in Washington, unveiled a new study that found a broad immigration overhaul would help the economy.

Advocates then boarded buses to the Capitol. Members of the group from Utah said that while they believed most of their House lawmakers were largely supportive of at least some form of an immigration overhaul, their goal was to persuade them to get out in front on the issue.

“It’s one thing to be with us,” said Todd Bingham, president of the Utah Manufacturers Association. “It’s another to lead out and actually create dialogue and create discussion and tell leadership in the House that we’re not interested in waiting two years — we need to address this now.”

The push comes as conflicting messages continue to emerge from the immigration debate on Capitol Hill.

Senator Marco Rubio, Republican of Florida and an author of the Senate-passed immigration bill that includes a path to citizenship for those immigrants already in the country illegally, seemed to backpedal slightly on Saturday. His spokesman told Breitbart News, a conservative news outlet, that House conservatives should not fall for a “ruse” that could lead to one of their more narrow, piecemeal immigration bills being used as vehicle to enter a conference negotiation between the House and the Senate, from which a broader immigration bill could emerge.

“On the surface, the statement didn’t read well,” said Alberto R. Cardenas, chairman of the American Conservative Union, when asked about Mr. Rubio’s comments. “But maybe a good explanation from him will be persuasive, so I’m going to hold judgment.”

Alex Conant, a spokesman for Mr. Rubio, said that the senator was not backing away from his support for the Senate bill, but simply reflecting the political reality in the Republican-controlled House, where many conservatives refuse to support any immigration bill because they fear it could be used as a “Trojan horse” and lead to amnesty.

“An ‘all or nothing’ strategy on immigration reform would result in nothing,” Mr. Conant said in a statement. “What is keeping us from progress on a series of immigration issues on which there is strong consensus is the fear that a conference committee on a limited bill will be used to negotiate a comprehensive one. We should take that option off the table so that we can begin to move on the things we agree on.”

Meanwhile, the group of business leaders from Utah remained intensely focused on their congressional delegation. Though they had scheduled meetings with only the four Utah House members, they were hoping to see Mr. Lee, their senator, who won election in 2010 with strong Tea Party support and has remained hesitant to support an immigration overhaul that he considers “amnesty.”

At roughly 11 a.m., good news arrived in the form of a text message: Mr. Lee would meet with them.

“Whatever is causing this issue to be stopped — whether it’s compromise, whether it’s breaking it into pieces — whatever is happening that’s blocking him from taking up a banner and being a leader on this, we want him to get over the barriers,” said Donna Milakovic, the executive vice president of the Utah Valley Chamber of Commerce.