Rep. Charles E. Schumer (D-N.Y.), one of the authors of the new immigration law, has criticized the Immigration and Naturalization Service for ordering all enforcement personnel to spend 50 percent of their time during the next year making "courtesy visits" to employers covered by the new law.

In a June 8 memorandum to regional INS officials, Commissioner Alan C. Nelson told subordinates to "devote half of our investigator time and a portion of other INS employe time to make these courtesy employer visits."

Nelson makes clear that the visits are to be only "informational. . . . These are not compliance efforts . . . {but are} to inform employers of sanctions and to elicit voluntary compliance."

Schumer called the decision "a dangerous misallocation of resources. . . . There are clearly more efficient ways to educate employers about their obligations than by having scarce investigative agents go door-to-door."

Under the new law, employers who knowingly hire illegal aliens face civil and criminal penalties of up to six months in prison and a $10,000 fine for each illegal alien hired for the first offense. The law provides a one-year grace period, which started June 1, in which first offenders receive a warning. Second offenders may be prosecuted.

The INS has not started giving warnings because of delays in providing copies of the rules and forms to employers. But an INS spokesman said yesterday that the information probably will be distributed by next week.

"While voluntary compliance is obviously desirable," Schumer said, "employer sanctions will not work unless the INS adopts a tough enforcement profile. By effectively delaying the implementation of sanctions for one year, the INS is sending the wrong signal."

He said the INS should rely on advertising, group meetings and telephone question-and-answer lines to educate employers.

Deputy INS Commissioner Mark W. Everson said the supplemental budget just approved by Congress contains funding for INS to hire nearly 1,000 investigators in the next year.

Schumer said there are now 680 investigators, a drop of 27 percent since 1976, and that the new law will increase their workload. He said that although INS soon may receive authorization to hire new investigators, the job requires 14 weeks of training and "very few of these new investigators are likely to be fully trained and on duty during this education period."