NEW YORK – Day laborers on foot from Long Island and Californians who sold tamales to pay for their trip are expected to rally on Sunday in Washington, D.C., with tens of thousands of immigrants, many of them undocumented Hispanics, to dramatize their pleas for immigration reform.

The laborers, walking more than 250 miles from Hempstead, N.Y., hope to join immigrants aboard more than 700 buses from at least 28 states and numerous caravans from the South and Southwest. The national attention they seek could instead be focused on Congressional votes on health care reform — one of the issues that has sidelined President Obama’s campaign promise of reform and possible legalization for the estimated 12 million people in the U.S. illegally.

To Martha Freire**, 48, of New York City, who worked to clean up the area around ground zero after the 9/11 terrorist attacks, immigration reform is about life and death. Undocumented and battling cancer, Freire wants desperately to see the two daughters she left behind in Ecuador 15 years ago — but she fears if she leaves, she won’t be allowed to return.

"I have cancer, and I want to see my daughters," Freire said in Spanish through a translator for the march. "It doesn’t matter if they don’t give me more benefits or anything, I want to see my daughters."

Rally organizers, a coalition of community, labor, business and faith groups, were hopeful as many as 100,000 marchers would arrive, said Shuya Ohno, a spokesman for the National Immigration Forum in Washington. The forum is among the organizing groups.

Reform advocates frustrated by the lack of progress met with Obama last week to press him on his stated commitment to fix the nation’s immigration system. Obama reiterated to them his commitment to reform and met with lawmakers who are drafting legislation; it is unclear if Congress will get him a bill this year that combines tougher border enforcement with a pathway to legalization.

Other issues pushed by the immigration groups include labor protection, a suspension of deportations until the bill is passed, an end to splitting families, and improvements in backlogs for legal visas.

In California, 400 members of nonprofit, labor, church and student groups set out by bus, car and plane, said Vanessa Aramayo, a director with the Los Angeles-based Council of Mexican Federations.

Aramayo said her group sold tamales and fruit salads at community events and street parties over the past few weeks to raise money for the trip. The Californians plan to meet congressional representatives from the state on Sunday before the rally, she said.

Organizers in the New York City area expected to send 200 buses, each with about 50 people aboard.

Among them will be Freire, who came to this country in 1995. She’s built a life here, giving birth to a daughter, working in child care, food service, cleaning. She said her work at ground zero caused the cancer in her neck.

"I’ve been here for a long time and I love this country," she said. Friere is going to the rally through a community group, Make The Road New York.

In Massachusetts, about 15 buses are scheduled to leave Saturday evening, according to immigrant advocates. A bus from Fitchburg, Mass., will transport some city’s large Uruguayan population while buses from New Bedford — the site of a 2007 raid of a leather-goods factory by federal immigration agents — will bring a large Central American group.

In Kansas, efforts to put together a caravan of buses and cars were being led by Spanish-language media outlets.

Beatriz Ledezma, president of Wichita’s bilingual newspaper Opinion, traveled to western Kansas to rally support on the airwaves of a Hispanic radio station in Dodge City. The newspaper planned to host an event at a Wichita supermarket featuring music and speakers to raise $1,700 to help pay for the trip.

"Nobody can afford it, nobody can take off work — but we are doing it," said community activist Dennis Romero.

Not everyone who thinks the country’s immigration system should be changed agrees with the rally’s call for legalizing the millions of undocumented immigrants already here.

That would be a mistake, and would only encourage others to come here illegally, said Heather Mac Donald, a fellow at the Manhattan Institute who has written on immigration.

She called for changing the system from the current emphasis on using family to determine who comes in to a system that allows entry to people based on their skills.

 "I don’t think that it’s in the long-term economic interest of the country to preserve the current immigration mix," she said. "It’s not what the 21st century economy needs."

Frida, a 21-year-old Peruvian who didn’t want to give her last name because of her undocumented status, said she would travel from Miami to support student immigration issues. She wants reform to allow high school graduates to continue their education or join the military as a way to become legal immigrants.

Arriving in the U.S. at 15 on a humanitarian visa to care for her dying father, she stayed after it expired; he died two months later.

She said she’s been an excellent student since arriving, never getting a grade less than a B despite having to learn English. She earned a scholarship that helped her get her associate’s degree at a community college, the only higher education available to her as an undocumented immigrant with limited funds.

Frida has undocumented friends who she says had the academic records to be admitted to top-level schools, like Johns Hopkins and Duke, but whose status has prevented them from fulfilling that potential.

"I know so many great, great, great kids that have amazing GPAs, that are incredible leaders of their communities, and they have no option," she said.

** Member of Make the Road New York.