SAN DIEGO, JUNE 3 -- Arrests of illegal aliens dropped about 60 percent here last month compared with arrests a year ago, immigration officials say.

The decrease, they said, is part of a downward trend since President Reagan signed immigration-revision legislation last November.

"It looks like people are just not coming," said Gene Smithburg, assistant chief Border Patrol agent for the San Diego sector of the U.S.-Mexican border.

"Either they're not taking the risk or they don't think they can get a job or they're waiting to see what happens with the legalization program," Smithburg said Tuesday.

However, Smithburg said it's too early to tell whether the decline will continue.

The immigration law is "being highly publicized in Mexico, as well as other Latin countries," he said.

Border Patrol agents caught 29,080 aliens in the San Diego sector in May compared to 73,269 in May last year, Smithburg said.

The law, which went into effect last month, provides amnesty for aliens who can document continuous U.S. residency since before Jan. 1, 1982. Aliens have one year to apply for amnesty.

The law also contains sanctions against employers who knowingly hire illegal aliens. These took effect Monday but won't be enforced for at least another month because of administrative delays.