The Reagan administration yesterday ordered a partial halt to the review of thousands of Social Security disability cases, following criticism that the program -- begun 18 months ago in an effort to crack down on ineligible recipients -- has stopped benefits for many persons who deserved them.

Health and Human Services Secretary Richard Schweiker and Social Security Commissioner John Svahn said in a statement that the number of reviews planned for the year beginning Oct. 1 will drop by 20 percent, to 640,000 instead of 806,000.

Administration officials began an accelerated program reviewing the eligibility of the 2.7 million disabled workers who receive benefits in an attempt to cut those people -- estimated at 10 to 25 percent of the caseload -- who do not meet the government's tough standards.

Despite yesterday's action, the number of reviews scheduled for next year still is 105,000 more than the number the government had difficulty performing this year.

This prompted Sen. Howard Metzenbaum (D-Ohio), the sponsor of a bill to slow down the reviews, to say yesterday, "We had all expected more. To increase the number of reviews is really cruel to the disabled receiving benefits."

Criticism of the program has been voiced by Republicans as well as Democrats and by disability recipients, groups representing the disabled and the beleaguered state officials who actually perform the reviews.

The Reagan administration said that 12 states, including Maryland, no longer will be sent new cases to review because of the huge backlog of cases they are handling.

Because of the backlog, about 56,000 case files have been held at Social Security headquarters in Baltimore since August.

The changes announced yesterday attempt to give state officials more time to handle the reviews. Eileen Sweeney, an attorney with the National Senior Citizens Law Center here, said the changes won't help much.

"The real questions are the unfair, rigid standards they are using to get the high rates of termination," she said.

In an effort to end the program's troublesome error rate, those now receiving disability checks will be told in face-to-face meetings with officials at local Security Security offices that their cases are under review.

Since the accelerated program was begun, many people have been dropped because state officials have been unable to locate them by mail.

Svahn said such meetings would prevent errors like a recent case in which an Illinois man in an iron lung was dropped from the rolls.

But advocates for the disabled said yesterday that while the change might eliminate some confusion, the state officials who actually review the cases still will not personally interview receipients.

Closer scrutiny of the $18 billion Social Security disability program began in March 1981.

It resulted almost immediately in a flood of complaints when many of the 157,980 people who have been dropped from the rolls protested that they are in fact too disabled to perform any type of work.

Of those who appealed their cases since the accelerated review began, 67 percent have been reinstated by administrative judges.