Washington - US presidential candidates Barack Obama and John McCain touted their economic plans and offered contrasting messages on immigration reform in duelling speeches to a prominent Hispanic group Tuesday in the US capital.

Obama said his administration would put the issues facing Hispanic Americans on a par with those facing all Americans and prevent employers from exploiting immigrant labour.

"It's about making sure that we have a government that knows that a problem facing any American is a problem facing all Americans," Obama, the presumptive Democratic Party nominee, told the League of United Latin American Citizens (LULAC).

While Obama promised to make immigration reform a "top priority" and to bring an estimated 12 million undocumented workers in the US "out of the shadows," his Republican rival McCain was more cautious in his own LULAC address.

McCain alluded to another effort at comprehensive immigration reform, but only after the porous US border with Mexico was secured and illegal immigrants were prevented from reaching the United States.

McCain has led two failed bipartisan bids in the last few years to reform immigration laws that would have offered a path to citizenship for those already living in the US illegally, albeit after paying a criminal fine and learning English.

"Many Americans, with good cause, did not believe us when we said we would secure our borders, and so we failed in our efforts (at reform)," McCain said.

"We must prove to them that we can and will secure our borders first. ... But we must not make the mistake of thinking that our responsibility to meet this challenge will end with that accomplishment."

But McCain gave few details of a future immigration plan. The Arizona senator is running a fine line between garnering Latino support and not alienating conservative supporters, who strongly oppose any form of amnesty for undocumented workers and have heavily criticized McCain for his past efforts at solving the problem.

Obama has held an edge of as much as 30 points over McCain in opinion polls among Hispanic voters in the United States ahead of November's general election. An estimated 9 million Latinos are eligible to vote.

Obama, a senator from Illinois, touted his past community work with Hispanic and other organizations in impoverished Chicago neighbourhoods, and said that McCain had "abandoned his courageous stance" in favour of immigration reform, since launching his presidential bid.

"We need a president who isn't going to walk away from something as important as comprehensive reform when it becomes politically unpopular," Obama said, but added that he too would require illegal immigrants pay fines and learn English if they wished to gain legal status.

Obama devoted much of his speech to specific problems facing the Latino community and was interrupted numerous times by applause and supporters who broke out into the now familiar chant of "Si se puede" ("Yes we can").

McCain, who spoke a few hours earlier, in contrast focussed on his economic plan for all Americans and reiterated his support for free- trade deals a week after travelling to Colombia and Mexico.

"The global economy is here to stay. We cannot build walls to foreign competition, and we shouldn't want to," he said.

McCain's remarks drew only tepid applause from the 200 to 300 people gathered in Washington's Hilton hotel, but no protests. Last week, McCain's speech was interrupted three times by demonstrators at the National Association of Latino Elected Officials (NALEO).

Democratic candidates have traditionally done well among Hispanics, who make up about 15 per cent of the US population, but Republicans have closed the gap somewhat in recent years.

The Democrats' 2004 nominee John Kerry won 53 per cent of the Latino vote compared to 44 per cent for President George W Bush, according to exit polls.

Former president Bill Clinton had garnered 72 per cent in 1996, compared to only 21 per cent for Republican challenger Robert Dole. (dpa)