The Immigration and Naturalization Service will offer extended hours this weekend at its local legalization office, 2990 S. Main, as the May 4 deadline for illegal aliens to apply for amnesty draws near.

Allan Speirs, chief legalization officer, said the office will be open from noon to 4 p.m. Saturday and Sunday.The office will be open regular hours, 8 a.m. to 3 p.m., May 2 and 3. On May 4, the last day to apply for legalization, the office will stay open until midnight.

Speirs said applicants will not have to submit full documentation. They can complete a simplified application and pay the fee, and then have two months to come up with additional documentation and medical reports.

The fee is $185 for those 18 and over and $50 for minors, with a maximum $420 for a family.

Aliens who entered the United States illegally before Jan. 1, 1982, and who have remained in the country since, are eligible to apply for legalization. Speirs said short absences of 45 days each, up to a total 180 days, are allowed.

Speirs said the number of people applying has picked up during the past few days as the deadline approaches. "Normally we have 15 to 30 come in during the day, but last week on a couple of days we had more than 70. Last week we averaged more than 55 per day."

Immigration officials don't know whether to prepare for a big last-minute crush, but Speirs said that when Canada offered a similar program, 10 percent of total applications came in on the last day.

"We're ready to be open long hours just in case," he said. "Even if they're in line before midnight, they will be served. No one will be turned away." So far the Utah office has processed more than 4,000 applications.

In addition, as a result of an order issued by the U.S. District Court in Washington, D.C., the INS will begin accepting applications from some people previously thought ineligible. A press release from the INS in Denver said previous regulations said people on a non-immigrant visa, for a temporary visit, had to show a violation of their immigration status was known to the INS before Jan. 1, 1982. Now they must only establish that documentation existed in one or more federal agencies, not necessarily the INS, before that date.