Secretary of State George P. Shultz warned Congress yesterday that the United States would have to drastically reduce refugee admissions for the next fiscal year if Congress sharply reduces the administration's $338 million budget request.

Shultz also said he would establish a new panel to review refugee operations in Southeast Asia. Department officials said they believed it was time for a fresh look at the issue. Shultz is expected to announce details of the panel soon.

Testifying at the annual refugee consultation meeting before a Senate Judiciary subcommittee, Shultz said the president proposes a ceiling of 70,000 refugee admissions to the United States for the coming fiscal year, including a ceiling of 3,000 for Latin America and the Caribbean "in the hope that Cuba will end its suspension of the U.S.-Cuban Migration Agreement of last December."

He said there will be a separate ceiling for admissions under the United Nations High Commission for Refugees Orderly Departure Program from Vietnam (ODP). The purpose is to reassure ASEAN countries (members of the Association of Southeast Asian Nations) that an expanding ODP will not mean a decrease in resettlement from first asylum camps and to send a clear signal to Hanoi that the U.S. is prepared "to make good on its offer to accept a large number of Amerasians and reeducation camp prisoners."

Since 1975, the United States has taken 125,000 Cambodian refugees. Shultz said this year the Vietnamese released almost 4,000 Amerasian children and family members compared with 2,200 last year. "The Vietnamese failed to reach our goal of 5,000 for the first year," he said.

Shultz said the United States will be meeting with Vietnamese representatives in Geneva next month. "We will be seeking agreement by Vietnam to improvements in the operation of the ODP which will enable more Amerasian children and other persons of special humanitarian concern to the United States to leave Vietnam, via this safe and humane route."

Robert Funseth, the department's senior deputy assistant secretary will once again lead the U.S. delegation this year.

Responding to questions, Shultz said the Reagan administration definitely plans to go ahead with a ban on the import of South Africa's krugerrand gold coins. He said the U.S. was in the process of "notification and consultation" prior to the ban.