SAN DIEGO -- Americans need to think of illegal immigrants as economic contributors and not law breakers, said five advocates for immigration reform Monday.

The five advocates, including a farming advocate and a U.S. Chamber of Commerce director, spoke during a press conference in response to a hearing held by the U.S. House Government Reform Committee. The Republican-led committee met Monday in San Diego to discuss the costs of illegal immigration to San Diego County's educational, health and legal systems.

Viewed in an economic sense, the advocates said, the loss of a labor force made up largely of illegal immigrants could cripple the nation's agricultural and other industries.

"Immigrants, legal or not, are woven deeply in the fabric of our society and economy," said Dick Castner, executive director of the U.S. Chamber of Commerce's western office. "If they were to disappear, the impact would be significant."

The five representatives spoke to promote action on immigration reform at the event sponsored by People for the American Way, a 900,000-member organization based in Washington, D.C., dedicated to countering conservative publicity. The group held the press conference to show that illegal immigrants contribute as much to society as they cost, if not more.

Several members quoted a recent Pew Hispanic Center report that discussed the importance of workers, including illegal immigrants, to fields other than agriculture, such as construction and hospitality.

Opponents of illegal immigration say illegal immigrants use American facilities, such as schools and hospitals, without paying income tax, and that helping illegal residents become citizens promotes law-breaking.

Luawanna Hallstrom, a board member for the Western Growers Association and California Farm Bureau, said it was wrong to say illegal immigrants don't contribute to American society because they don't pay income taxes. She said illegal immigrants pay several taxes, from sales taxes to property taxes.

"These people never see anything from that money," she said. "We haven't given them the legal means to participate."

Dan Siciliano, executive director of the Law, Economics & Business program at Stanford Law School, said something had to be done to meet future U.S. labor needs. He said retiring baby boomers and a national birth rate under two per American female are going to strain the U.S. work force and make it difficult to sustain economic growth.

The advocates supported the recent U.S. Senate bill, passed in May, that includes a temporary work program and more access to citizenship for illegal immigrants. They preferred that bill over a U.S. House bill, passed in December, that calls for a crackdown on immigration enforcement.

Contact staff writer Patrick Wright at (760) 739-6675 or e-mail: pwright@nctimes.com.