A shortage of the most common type of blood forced some hospitals to cancel non-emergency operations Saturday in a crisis officials blamed on donor fears of contracting AIDS, health service bureaucracy and public complacency.

For at least 24 hours, radio stations in London appealed for donors with type-O blood to come forward, but many transfusion centers where donors lined up were closed until Monday."People in London are simply not giving blood as they used to. We have reached a crisis," said Marcela Con-treras, director of the North London Blood Transfusion Service. "We now have 85 units which is below our emergency stock level."

Supplies in Manchester were also reported down but not as low as in London.

"I would not characterize this as a crisis," said Health Service spokesman Paul Hayward. "It is only a case of major operations being postponed at some hospitals until blood arrives, and the response to the appeal has been very good so far, as it always is."

"AADS has been with us for five or six years now and we've learned how to cope with it," Hayward said. "But what happens is that some donors think they can contract the deadly disease by giving blood.

"Such fears are completely unfounded."