Suspected drug smugglers deposited about $108 million in Miami banks during a one-year period, according to a secret Treasury Department report that traces the flow of money from south Florida to Colombia.

The report is the only document to surface that identifies major bank depositors suspected of laundering drug money here, the banks they use, their bank account numbers and details of their financial deals. Most of the depositors named are Colombian nationals who operate money exchanges in the United States and Colombia.

The report does not suggest that the Miami banks solicited deposits from drug smugglers, not that they were aware that some of their depositors were suspected of laundering drug money.

One Colombian, Arturo Fernandez, "who appears to be a key principal in laundering millions of dollars generated from drug smuggling in Florida," deposited more than $32 million in Miami banks in 1978, the report said.

"The scope and magnitude of these deals are incredible," said one federal narcotics agent. "We have gigantic targets to work on. We should be working on them day and night."

Federal authorities say drug organizations annually launder far more than $100 million in Miami banks.

"Based on our experience, $100 million is a conservative figure," Arthur F. Nehrbass, head of the Miami FBI office, said.

Investigators from four federal agencies, including the Treasury, are using bank records to identify major drug-smuggling organizations operating in south Florida and Colombia. The Senate Banking Committee is holding hearings into the movement of drug money through Miami banks. [See story D7.]

The biggest portion of the money -- $95 million -- was deposited in the Continental National Bank of Miami. Continental officers refused to comment on the report. Previously they have said the bank has never knowingly transacted business with anyone involved in drug smuggling.

Treasury agents and federal bank examiners have traced deposits made by suspected drug smugglers -- or the money exchange houses that they employ -- to 12 other Miami insititutions.

The report, completed last year, is not considered comprehensive; it is based almost entirely on federal audits of only a handful of Miami's 30 federal banks. The audits cover transactions made in 1978.

Deposits made by suspected drug smugglers were traced to Continental Bank, $95 million; Bank of Miami, $5.73 million; Royal Trust Bank of Miami, $3.6 million; Central National Bank, $2.5 million; Southeast First National Bank, $900,000; Manufacturers National Bank, $800,000; Biscayne Bank, $260,000, and Pan American Bank, $200,000.

Other banks that recieved small deposits from suspected drug smugglers include the Bank of America's International branch here, Second National Bank of North Miami, Flagship National Bank, People's Downtown and the Northside Bank of Miami. Miami.

Only one of the audited banks, the First National Bank of Greater Miami, was found to be free of suspected drug money.

Officers of the banks named in the report said they were unfamiliar with the secret document and had not been notified by federal officials of any improprieties. The bankers said they did not welcome deposits of drug money and were doing whatever they could to exclude them.

"I'm not surprised" about the report, Justo Legido, Bank of Miami president, said. "Most banks in this area have the same problem."

Dave Wollard, president of Southeast First National Bank, Florida's largest, said: "When you consider how much money moves through Miami banks ever day, the number of bank transactions and the volume of money, you can understand why it's so difficult to pick out a few suspicious transactions."

Most of the deposits mentioned in the Treasury Department Report were made by five Colombian nationals who have alleged ties to drug smugglers in the United States and Colombia. The Colombians made hundreds of deposits in Miami banks in 1978, the report said.

Wollard and other Miami bankers interviewed said they were trying to watch large cash depositors. The bankers also said they were complying strictly with federal requirements that trasactions involving more than $100,000 be reported to the Internal Revenue Service.

But the Treasury report listed four Miami banks that had failed to comply with those requirements, at least some of the time. Banks were Central National, Continental National, Manufacturers National and Pan American. Officers of the four banks disputed the Treasury Department's finding.

"Our bank has a very firm policy of reporting all transactions that must be reported," Continental's attorney, Gary Lipson, said.

The unprecendented flow of drug money laundered here attracted national attention last year when the Federal Reserve Bank of Miami reported a $5 billion cash surplus, the largest in the nation.

Two large-scale federal investigations using bank records to identify major drug smuggling organizations are also under way.