Treasury Department officials say the 26 million social security checks due next month may be delayed unless Congress acts quickly on a special appropriation to keep the department's employes working, its computers going and pay its mammoth postage bill.

The Bureau of Government Financial Operations, which mails out more than 750 million checks a year--for Social Security, VA benefits, federal pay and annuity checks--is waiting for an emergency $81.6 million appropriation. Officials say that without the appropriation, the bureau will not be able to put the checks in the mail on May 27 and 28 to ensure delivery in early June.

Earlier, Treasury officials were hopeful that they could process the checks even if the special supplemental was still blocked by congressional infighting or the president's threat to veto a bigger money package than agencies had requested. But now top officials say they are afraid to violate the antideficiency act which prohibits federal officials from spending money that has not been appropriated.

Treasury, the Labor Department and a number of smaller agencies have asked Congress for emergency funds to help cover the cost of last October's federal pay raise, or to fund specific programs.

Postage rates went up last year, from 18 cents to 20 cents for a first-class letter but the BGFO's budget has not been increased to reflect the extra cost. It has been reimbursing the Postal Service monthly for checks mailed out at the new rate, but now the bureau says it does not have enough money to pay the full rate for June checks. Part of the emergency supplemental it requested includes $9 million for the added postage costs.

The House has passed legislation that would meet the financial needs of most departments. But it added more than $1 billion in funds for programs that the Senate is not likely to accept, and that the president has said he would veto.

So as of the moment, Treasury's position is that it cannot get the checks out on time unless Congress quickly approves its budget requests or gives it some sort of exemption to put the checks in the mail despite the lack of funds.