NEW ORLEANS (AP) _ A lucrative underground trade in cash is flourishing between Cuban exiles in the United States and their island homeland just 90 miles off the Florida coast, despite an economic embargo and a specific ban on dollar transfers.

Millions of dollars are being smuggled into Cuba in bulging money belts or quietly funneled through third-country banks. An upcoming U.N. report says that in 1996, individual exiles and private organizations illegally sent Cubans more than $1 billion, channeling more hard currency into the Cuban economy than either tourism or sugar exports.

Most of the money comes from Cuban exiles such as Amaury Almaguer, a New Orleans insurance agent and publisher of a Spanish-language monthly. Every month for the last 15 years, Almaguer has sent $200 back home to Cuba, where his parents and siblings still live. He uses a Canadian company to get the money into Cuba.

``Each day it is worse,'' Almaguer says of the Cuban economy. ``The difference is between those that have dollars and those that do not have dollars. If you don't have dollars, you don't eat. And Cuba doesn't pay its workers with dollars. If you have pesos, you can't buy anything.''

Nearly half of the people in Cuba receive economic help from family and friends in the United States, said Amando Lago, a director of the Washington-based Association for the Study of the Cuban Economy _ even though it's against the law.

President Clinton banned cash remittances shortly after Cuban fighter jets shot down two civilian planes flying near Cuban air space Feb. 24, 1996, killing four members of the Miami-based exile group Brothers to the Rescue.

The U.N.'s Economic Commission on Latin America and the Caribbean estimates that of the $1.1 billion sent to Cuba last year, $800 million came from family remittances. And that's just cash. It doesn't include the value of food, medicine and other goods.

To put that much cash into perspective: Cuba's tourism receipts for 1996 were $1.4 billion, sugar exports were $1 billion, and all other exports totaled less than $1 billion. In terms of net income, money that actually stays in Cuba, exiles account for more than Fidel Castro's government makes from sugar or tourists, says analyst Ernest Preeg of the Washington-based Center for Strategic and International Studies.

While nobody knows precisely how many dollars are sent to Cuba _ exile groups estimated family remittances at closer to $400 million before the U.N. report _ no one disputes the money goes a long way toward feeding the Cuban people and keeping Castro in power.

Squeezed by worsening shortages since the former Soviet Union cut off aid, Cubans are turning with increasingly desperate pleas to family members in the United States.

A Cuban mother sent her family in Miami a letter with the footprints of her children traced on sheets of paper. ``Please send shoes,'' she wrote.

Dollars became the de facto currency of the island in 1993, when Castro legalized the use of American currency. As shortages worsen, ``dollar-only'' stores have become the only places Cubans can get many of life's basic necessities.

Humanitarian aid _ such as food and medicine _ to Cuba is legal under the Helms-Burton Act, which sanctions foreign companies that invest or do business using confiscated U.S. property in Cuba.

Shipping companies typically charge $10 to $15 a pound to ship anything into Cuba. But some shippers and travel agencies in Miami and New Orleans, cities with large Cuban populations, also tell callers openly they will take cash into Cuba _ for a price. Most ``mules'' take a 10 percent to 20 percent cut. Some tourists pay for their vacations to Cuba by taking in cash for others.

Sending money to the homeland remain a divisive issue in the exile community _ torn between the pleas of poverty-stricken Cuban relatives and the exiles' own unrelenting dream that the U.S. embargo will somehow drive Castro from power.

Some exiles blame Castro _ who has referred to the exiles as ``gusanos,'' or worms _ for encouraging Cubans to ask their family members for the much-needed dollars. They say the cash flow is now so great that the Cuban people have come up with their own nickname for their American relatives: They call them ``gusanos verdes,'' or green worms.

``The embargo is being openly flaunted, and everyone knows. It is a disgrace,'' said Antonio Jorge, Cuba's former chief economist and now an economics professor at Florida International University in Miami. ``It is a matter of conscience. I do not oppose sending strict humanitarian aid, but I oppose what is taking place now.''

The bulk of the money is coming from the most recent immigrants who still have close family ties on the island, such as those who came over in the 1980 Mariel boat lift. Little cash comes from older exiles, whose families have either already fled Cuba or have died.

The U.N. report estimates that the amount of U.S. dollars going to the country in 1996 almost doubled from 1995, when remittances totaled just $532 million. Most economists attribute the huge jump to a statistical fluke caused by the Cuban government reporting family remittances for the first time.

``It is a lot of money. It is significant to the degree a lot of exiles are willing, even illegally, to send large amounts to support their families,'' said Miami businessman Teo Babun. ``It helps to demonstrate why there has been, if nothing else, a stability.''