Agricultural workers who are in the country illegally have until midnight to apply for immigration amnesty, a deadline that is passing quietly and is tainted with charges of fraud.

Federal immigration offices around the country braced for a last-minute rush as the final call is made for the illegal aliens' applications for U.S. residency.Under a special provision of the 1986 immigration law, foreign farmhands must prove they harvested fruits, vegetables or other perishable crops in the United States for at least 90 days in a one-year period that ended May 1, 1986, to be eligible.

Several people were waiting outside the door when the Salt Lake Legalization Office of the Immigration and Naturalization Service opened at 8 a.m. Wednesday.

Legalization adjudicator Vicky Stirland said the office has been processing 35 to 40 new applications per day for the past week or so, and she guessed that as many as 100 to 150 would come in on the final day.

More than half of the applications filed for the Special Agricultural Workers Program have come from California, followed by Florida with about 10 percent and Texas with about 8 percent. Significant numbers have also been filed in the Northwest, Arizona and New York.

Under the initial phase of the legalization program that ended May 4, temporary residency was granted to more than 1.7 million illegal aliens who proved continuous residency in the United States since Jan. 1, 1982.

The Immigration and Naturalization Service had estimated that 600,000 farm workers would apply for the latest program. The figure topped 1 million by the first week of November, and up to 200,000 more are expected before the filing period ends, said Aaron Bodin, who heads the program in Washington, D.C.

But in a last, desperate chance to become legal U.S. residents, many farm workers are using fraudulent documents to prove they worked here to qualify.

Many farmhands unable to obtain the needed documents turn to labor contractors who hire illegal immigrants, many of whom write letters to anyone who asks, for a fee, Bodin said.

Mary Lopez, the California-based director of the Martin Luther King Jr. Farmworkers' Fund, said she's heard of people paying up to $800 for a phony letter.

In Denver, Donald H. Russell, INS district director, said more than 20 percent of the documents filed in Colorado, Wyoming and Utah were fraudulent. "But we haven't reviewed a lot yet," he said. "We expect it will go higher."

In the Western states in recent weeks, 70 percent of applications filed have been recommended for denial, officials said.

Although it appears many will ultimately be approved, immigration officials say the final denial rate may be as high as 50 percent.

In the Northeast, more than 40 percent of the almost 20,000 applications were fraudulent, said Amy Otten, an INS spokeswoman in Burlington, Vt.

"Fraud was high throughout the Eastern region, especially in larger metropolitan areas," Otten said.