So-called mulas (mules) take flights to Cuba, carrying clothes for resale as well as supplies for hairdressers, private restaurant owners, manicurists and others who have gone into business for themselves. Mulas also arrive from other countries, but the Miami connection is the most active.

Sanchez said IPC turns away shipments that are obviously commercial. “If someone comes in here with 30 pairs of flip flops or 30 watches, we say we can’t send it. It’s not a humanitarian shipment. We had to escort one man off the property who was insisting,’’ he said.

Analysts say it appears the government’s intent is to cut off commercial shipments masquerading as humanitarian aid and to encourage more Cubans to buy supplies for their small businesses at state stores.

“This could be the end of the mules,’’ said Sanchez. “There are some handlers who manage networks of 150 mules. They have stopped operations. They are terrified (of a crackdown).”

But Cuba’s new entrepreneurs complain that the merchandise at state-run dollar stores is scant, the prices are high and they need to get the supplies to run their businesses from somewhere.

During a National Assembly meeting last month, Marino Murillo, Cuba’s economy czar, said establishment of wholesale markets is under study but he didn’t offer specifics.

“I think this is an example of the government shooting itself in the foot,’’ said Ted Henken, a professor at Baruch College. “Yes, every government needs some kind of tariff controls,’’ he said, but a big rise in fees “cuts the floor out from incubating businesses.’’

Meanwhile, those who ship packages to their families said they’ll wait and see what happens in September. Mercedes Martinez, of West Palm Beach, whose recent parcel to her mother in Cienfuegos included a flat screen television, food and medicine, said she was wary about hefty new Customs fees. “It’s still reasonable now,’’ she said, “but when it goes up, we just won’t be able to send as much.’’