* Obama meeting with immigration reform advocates, CEOs
* Activists warn against linking overhaul to security
* Details of guest worker program still an issue
By Mark Felsenthal and Roberta Rampton
WASHINGTON, Feb 5 (Reuters) - Immigration reform advocates urged President Barack Obama on Tuesday to reject Republican congressional proposals that would delay a path to citizenship for undocumented immigrants by making changes contingent on stepped-up border security.
After meeting Obama at the White House, the activists told reporters they had pressed the president to ensure reforms provide an unambiguous route to citizenship for the estimated 11 million people who are in the United States illegally.
"He's not going to accept a vague path to citizenship," said Janet Murguia, president of the National Council of La Raza, stopping short of saying that Obama had explicitly rejected linking reforms to increased border security.
The groups said they were "aligned" with Obama's plan on immigration, which he outlined in a Las Vegas speech last week.
That plan would give illegal immigrants a clear process to achieve citizenship, including payment of fines, criminal background checks and going to the "back of the line" behind legal applicants.
Obama has vowed to introduce his own bill if Congress fails to act in a timely fashion.
But top Republicans want to defer citizenship until the country's borders are more secure, especially the frontier with Mexico. A bipartisan group of senators is drafting a bill that could include such a trigger.
"We expect there to be language around the trigger, but it can't be a false trigger," Murguia told reporters.
"It can't be a trigger that keeps moving the goal posts and is indefinable. So it has to be meaningful, real and tangible for us to accept it," she said.
The White House says it believes Obama has already addressed most border security goals sought by Republicans, spokesman Jay Carney told reporters.
But Carney said Obama would wait until senators draft a bill before judging any proposed trigger.
The groups vowed they would make their opinions heard in Congress, and noted that the Latino electorate overwhelmingly backed Obama in the Nov. 6 presidential election and are counting on quick action on the issue.
"Our community feels momentum and our collective power," said Marielena Hincapie, executive director of the National Immigration Law Center.
The Republican-controlled House of Representatives held its first hearing on the issue on Tuesday and questioned the idea of providing a path to citizenship for illegal immigrants.
GUEST WORKERS AN ISSUE
Senators have also proposed an improved guest worker program, a top issue for the agricultural industry, which counts on immigrant workers to pick crops, and for labor groups, which have opposed such proposals.
Richard Trumka, president of the AFL-CIO, the nation's largest federation of unions, told reporters that the group discussed a "data-driven system" for guest workers.
"We can fix what's wrong right now and prevent what's wrong from driving down the wages of everybody else," Trumka said.
While details of a new guest worker program still need to be worked out, labor unions are eager to help shape a program to benefit their members, said Frank Sharry, executive director of America's Voice, a group advocating for immigration reform.
"The good news is that labor is united and wanting immigration reform. That was not the case a few years ago," Sharry told reporters.
Later on Tuesday, Obama is also slated to meet with chief executives from 12 companies on immigration reform and other issues, including Goldman Sachs Group Inc's Lloyd Blankfein, Yahoo Inc's Marissa Mayer as well as Arne Sorenson of Marriott International Inc, Jeff Smisek of United Continental Holdings Inc, and Klaus Kleinfeld of Alcoa Inc.