Federal agents in Miami seized a cocaine-production laboratory and shut down two operations that were laundering illegal drug profits, assistant Treasury secretary John Walker said yesterday.

Customs Service and Internal Revenue Service agents arrested 11 persons and recovered $3 million and 40 pounds of cocaine, with an estimated street value of $10 million, Walker said. He said those arrested were laundering up to $180 million a year in currency.

The arrests came seven days after President Reagan announced a nationwide crackdown on drug trafficking; Walker called this "a complete coincidence." The raids were part of Operation Greenback, a South Florida investigation that has produced 125 arrests since it began at the end of the Carter administration.

Treasury Department officials say they have been concentrating on bank accounts through which drug traffickers try to transfer profits out of the country. They are doing this in part by monitoring forms required on bank deposits exceeding $10,000. Walker said that neither the suspects nor the banks filed the forms in this case, however. He added that the banks had cooperated in the probe.

"Individual traffickers can be taken off the street and put behind bars, and quantities of drugs can be seized," he said. "But when we can seize this money, it has much more of an effect of disrupting the organizations involved."

Carlos Uribe, one of seven members arrested from a group headed by Eugenia Zapata, was seized before boarding a flight to Panama with $346,000 in cash, Walker said. In the second case, four Cubans connected to a bank account in the name of Jeremy Investments were arrested and $2.3 million recovered, he said.