State and local government officials fear they may have to ante $50 million a year out of their own treasuries if the Department of Health and Human Services goes ahead with a plan to cut reimbursements to the states for refugees' welfare and medical aid.

The plan, outlined in a confidential memorandum and budget document, would cut federal payments to the states by more than $100 million a year below what they would be under current law.

"In some cases we will be able to reduce benefits as the federal reimbursement is cut off," but in other cases "we can't let these people starve or die of disease," said an official of the State and Local Coalition. He estimated that the net extra state outlays could range from $40 million to $50 million a year.

The coalition consists of the National Association of Counties, the National Governors' Association, the National Conference of State Legislatures, the National League of Cities and the U.S. Conference of Mayors. They contend it is unfair for the federal government to dump costs on them for what is basically the result of federal immigration policy.

Under existing policies, special aid goes to refugees for the first 36 months they are here, if in need.

In the past, the United States has been picking up 100 percent of the states' welfare cost for refugees if they meet eligibility rules for state welfare payments under Aid to Families with Dependent Children, Supplemental Security Income or Medicaid. (In contrast, for Americans who get benefits under these programs the federal reimbursement is often as low as 50 percent.)

Refugees who do not meet AFDC, SSI or Medicaid requirements but who are nevertheless poor or sick get equivalent benefits for 36 months; the United States has been reimbursing the states for the entire cost. About 55 percent of all assisted refugees are in this group, and it is reimbursements for this group that HHS Secretary Richard S. Schweiker is thinking of cutting.

The option that he has decided on, according to sources: fund most benefits for this group only for 18 months.

The local and state governments are focusing their complaints on the appropriation that applies to Vietnamese and other non-Cuban, non-Haitian refugees.

According to the HHS budget document and memorandum, HHS, as a result of White House budgetary decisions, has scheduled only $525 million in fiscal 1982 to reimburse the states for support, medical assistance and social services to all refugees other than those from Cuba and Haiti. This figure, already publicly known, is at least $160 million below what federal reimbursements to the states would be under current policy guidelines.

For fiscal 1983, the HHS budget document foresees holding outlays to about $546 million, a previously secret figure which, according to the documents, is about $130 million less than would be disbursed under current policies. This figure could go up or down a bit depending on which reimbursement cuts are put into effect. The states can compensate for part of the cut by reducing benefits they pay for, but as for the rest, "We'll have to eat the extra cost," said one official unhappily.