(Adds quotes from announcement, Senators' comments.)
By Roberta Rampton and Rachelle Younglai
WASHINGTON, March 18 (Reuters) - President Barack Obama on Monday nominated Tom Perez, head of the Justice Department's Civil Rights Division, as labor secretary, a Cabinet member who will play a key role in the administration's efforts to raise the minimum wage and reform immigration laws.
Perez is the only Latino nominated to Obama's second-term Cabinet so far. The Harvard-educated civil rights attorney is expected to face opposition from some Republican senators who say he has been too aggressive on certain immigration issues, and too political.
Obama urged the Senate to quickly confirm Perez, who he said would be an integral part of his economic team.
Perez, the son of immigrants from the Dominican Republic, helped pay for college by working as a garbage collector and in a warehouse, said Obama, who described Perez's career as exemplifying the American success story.
"If you're willing to work hard, it doesn't matter who you are, where you come from, what your last name is - you can make it if you try," Obama said. "Tom's made protecting that promise for everybody the cause of his life."
Perez's nomination was championed by Hispanic groups, which have pushed for more representation in the Cabinet.
Perez made brief remarks in Spanish and English at the event, which was attended by top union leader Richard Trumka of the AFL-CIO labor federation and Benjamin Todd Jealous, head of the NAACP, the nation's largest civil rights group, among others.
Perez said he looked forward to meeting with senators from both parties.
But Perez is expected to face tough scrutiny from Republicans like Senator Jeff Sessions of Alabama, who called Perez "the wrong man for this job" and criticized him for being too aggressive helping undocumented immigrants find work as part of an advocacy group called Casa de Maryland.
"His views on illegal immigration are far outside the mainstream," Sessions said in a statement.
Senator Chuck Grassley of Iowa, the top Republican on the Senate Judiciary Committee, has also expressed concerns.
But Democratic Senator Patrick Leahy, head of the Judiciary Committee, called Perez a "fierce defender of workers' rights" who is "uniquely suited" for the job and should be confirmed.
(Additional reporting by Jeff Mason, Mark Felsenthal and Thomas Ferraro; Editing by Eric Beech)