Immigration officials in San Diego say they will start a pilot program Tuesday asking people who are in the country illegally to leave voluntarily, a plan that advocacy groups on both sides of the issue said probably will not work.

The program was designed to give illegal immigrants who have been ordered to leave by an immigration judge an opportunity to work with officials to ease their deportation, said Lauren Mack, a spokeswoman for Immigration and Customs Enforcement in San Diego.

San Diego is one of five enforcement offices around the country that will be taking part in the trial program, which is scheduled run through Aug. 22. The other offices are in Santa Ana; Phoenix; Chicago and Charlotte, N.C.

The program will give people up to 90 days to make arrangements to leave the country, Mack said. It also will help people avoid the expense of being arrested and deported by immigration agents, which some immigrant rights groups say can be traumatic for families.

"It's a program designed to invite any immigration fugitive with a final deportation order and no criminal record to come into our office and work with us," Mack said.

One benefit of the program is that financially strapped illegal immigrants from anywhere in the world may be eligible to get plane tickets paid for by the agency, Mack said.

There are about 550,000 people in the country who have been ordered deported but have not left, Mack said, adding that about 5,700 of those people are in San Diego and Imperial counties.

Pedro Rios, an immigrant rights advocate with the human rights group American Friends Service Committee in San Diego, said he does not expect a big rush of people turning themselves in.

"I think it's unlikely that people will respond to it," Rios said.

That's because when people leave, it will be harder for them to come back and reunite with their families, Rios said.

Increased enforcement along the border makes it more difficult to come back illegally. And those people who are deported are often barred from returning through legal channels for 10 years or more.

Illegal immigrants have always had the option of leaving on their own, said Jeff Schwilk, who leads the San Diego Minutemen, a North County-based, anti-illegal immigration group.

"If ICE is giving some of them the grace period to help convince them to leave before they get caught and formally deported, that sounds like the humane treatment of illegal aliens that the Latino activists have been demanding," Schwilk said.

Though there may not be many illegal immigrants willing to take the offer, even if a few do turn themselves in, that would save enforcement agents the time, effort and expense of going after them, some activists say.

Mark Krikorian, executive director for the Center for Immigration Studies in Washington, an organization that advocates stricter immigration policies, said that he, too, does not expect a rush of people leaving voluntarily.

When asked whether he thought the program would be successful, he said: "I wouldn't bet more than a stick of gum."

But it is worth a try, Krikorian said.

"I don't think there's a down side to it," he said. "It's not quite as silly as people are making it out to be."

Contact staff writer Edward Sifuentes at (760) 740-3511 or esifuentes@nctimes.com.