* Republican opposition looms
* Formerly worked on Kennedy staff, in Maryland government
* Adds Latino voice as administration works on immigration issues
President Barack Obama on Monday nominated Tom Perez, head of the Justice Department's Civil Rights Division, as labor secretary - a job that would give him a key role in the administration's efforts to raise the minimum wage and reform immigration laws.
Perez, 51, is the only Latino nominated to Obama's second-term Cabinet so far. He is expected to face opposition from some Republican senators who say he has been too aggressive on certain immigration issues and too political.
Obama described Perez's career as exemplifying the American success story, noting Perez, the son of immigrants from the Dominican Republic and a graduate of Brown University and Harvard Law School, helped pay for college by working as a garbage collector and in a warehouse.
"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 has worked on civil rights issues in a number of government positions, including as labor secretary for the Maryland state government, and as an elected council member for the Washington suburb of Montgomery County, Maryland.
He also spent time working as a special counsel to the late Democratic Senator Edward Kennedy on civil rights, including immigration reform issues.
Obama urged the Senate to confirm Perez quickly. He said he would be an integral part of his economic team as the administration works with Congress to try to overhaul immigration laws to give the country's 11 million illegal immigrants a pathway to citizenship.
Obama also has proposed increasing the minimum wage to $9 per hour from its current level of $7.25, an initiative that the Labor Department has been promoting around the country.
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 his introduction, which was attended by 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.
"At a time when our politics tilts so heavily toward corporations and the very wealthy, our country needs leaders like Tom Perez to champion the cause of ordinary working people," Trumka said in a statement.
SESSIONS: 'WRONG MAN FOR THE JOB'
There were early signs that Republican senators could raise objections to the confirmation of Perez.
Republican Senator Jeff Sessions of Alabama 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 David Vitter, a Republican from Louisiana, said he would block Perez's nomination until the Justice Department answered questions about enforcement of the National Voter Registration Act in his state.
Charles Grassley of Iowa, the top Republican on the Senate Judiciary Committee, said he was concerned about Perez's role in persuading the city of St. Paul, Minnesota, to withdraw a Fair Housing Act case from the U.S. Supreme Court last year.
The case would have tested protections for racial minorities against predatory lending. Some federal officials feared the conservative-dominated court might have issued a decision curtailing those protections.
Grassley said congressional investigators were looking into the deal the Department of Justice struck with St. Paul as it sought withdrawal of the case and whether it involved backing off a separate legal claim against the city.
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.