South Florida's international trade sector, which has reliably created jobs and generated revenue for the region, is in the midst of the worst slump in recent memory.

After years of steady trade growth, South Florida exporters and importers are dealing with weak demand for merchandise and lower prices for many exports, as well as a lack of trade financing from banks -- a problem that's especially acute for small and mid-size firms.

``Banks are being extremely shy and conservative, and this is clogging up trade,'' said Gary Goldfarb, executive vice president at WTDC, a Miami-based supply chain infrastructure company that handles imports and exports for a range of clients.

``Customers overseas need to buy products so they can sell products. The whole system is choking up,'' he said.

Exports and imports for the Miami Customs District, which includes Miami-Dade, Broward and Palm Beach counties, are down $6.4 billion for the first five months of 2009, or 14.7 percent below the same period last year, according to U.S. Census Bureau figures compiled by World-City, a Miami-based media company that tracks international trade.

When trade suffers, so does the regional economy. More than 850,000 Florida jobs depend on international trade, and there are about 44,000 exporters, most of them concentrated in South Florida, according to Enterprise Florida, the state public-private sector partnership that promotes economic development.

Michael Martínez, operations manager at Export-America Co., a small Miami company that sells replacement parts for specialized machinery and heavy equipment to Latin American clients, says business is down to less than half of what it was two years ago -- due mainly to a lack of credit for overseas buyers.

``Our providers don't give credit, and customers can't get financing'' he added. ``For small business, credit is not there, and that has affected our business drastically.''

General Ceramic Tile & Stone, a Doral-based importer of ceramic tile and flooring, has seen sales fall by 40 percent this year as the construction industry remains in a prolonged slump, said owner Diego Acosta.

In this case, weak product demand is the problem, not financing, since the company has 90 to 120 days to pay for merchandise bought from ceramics factories overseas.

Before the banking crisis struck in 2008, most exporters shipped merchandise to foreign customers under open accounts. This means goods were shipped and delivered to customers and payment became due, usually in 30 to 90 days.

This system creates a risk for the exporter -- who is financing the transaction -- but is advantageous for the buyer. Exports were also financed via letters of credit, documents issued by a bank that guarantees payment to the exporter, or by other methods.

As trade numbers dip, jobs are lost.

Some export-import businesses, especially small firms, have closed their doors.

Among evidence of the slowdown:

• Law firms, architects, accountants and others who export services have seen business languish as overseas projects are killed or put on hold. Some of their overseas clients, suffering from the recession in their home countries, are slow to pay their bills or have stopped paying altogether.

• Franchisees can't obtain financing to buy equipment for new operations overseas, said José Rojas, a Miami attorney who specializes in international business transactions and litigation.

• Trading companies are playing it safe. Rick Carral, a broker at ACG Brokerage in Miami, said companies are taking up defensive positions and avoiding risk at all costs. ``People aren't taking any risks in new endeavors,'' Carral said.

``They're only dealing with established customers,'' he added.

Analysts say demand for merchandise here and abroad won't recover significantly until the world economy improves, or until customers exhaust current stocks.

And what demand remains is being choked off for many companies because of banks' reluctance to engage in trade financing.

``We have a financial crisis because banks have cut back on our credit card lines,'' said Michael Taylor, part owner of Caribbean Exporters in Miami. Caribbean is a small company that sells machine parts to clients in the English- and Dutch-speaking islands.

Taylor said the family-owned company, which has three employees, has been forced to use its own cash to finance operations since banks have reduced limits on their credit cards, their only source of outside financing.