Business groups and port officials are raising new objections to transferring the Customs Service to a new Homeland Security Department.

Putting the emphasis on stopping terrorism, they complain, could disrupt the efficient movement of goods and people across U.S. borders, cutting into profits and damaging local economies.

"Congress should not let this enhanced focus on security compromise the traditional responsibilities of U.S. Customs," said Timothy Farrell, deputy executive director of the Port of Tacoma, Wash. "U.S. Customs is an integral link in our nation's economic chain of commerce."

The 300 U.S. entry points — land border crossings, international airports and seaports — have become busier since 1994, when the North American Free Trade Agreement eliminated many barriers with Canada and Mexico.

Last year, international trade was valued at $1.3 trillion and 472 million people entered the United States. The importers, exporters, brokers and other companies involved in all this activity say the nation's economic vitality could be threatened if Customs becomes mainly an anti-terrorism agency.

"It is the worst fear of many that trade facilitation will be almost entirely neglected in a humongous new department devoted almost entirely to security and enforcement," said James Clawson, chief executive officer of an international consulting firm and a member of the Joint Industry Group, representing 160 firms active in foreign trade.

Customs also is a key part of the war on illicit drugs, seizing more than 1.7 million pounds of marijuana, cocaine and heroin and 9.5 million tablets of Ecstasy in 2001, according to the National Treasury Employees Union. In late June, officials in Texas and New Mexico seized over 5,000 pounds of marijuana in several busts.

As Congress returns this week from a holiday and begins putting together legislation to create the new department, its impact on trade remains an unsettling issue, particularly to lawmakers representing major exporters.

Rep. Jennifer Dunn, R-Wash., whose state is home to Microsoft Corp. and Boeing Co.'s manufacturing operations, among others, said "a lot of us are interested in exactly how this will work. We don't want to slow down the passage of products."

There already are frequent complaints from businesses about long lines at many border crossings, particularly in the Southwest. At seaports, there are concerns that Customs officials at one place require more costly and time-consuming unloading of shipping containers than at others.

Ultimately, industry officials say that if these kinds of problems become a lower priority once Customs is transferred, the economy could suffer. Importing and exporting costs would rise, perhaps leading cargo to being diverted to ports in Canada and other countries, threatening thousands of U.S. jobs, they argue.

Bush administration officials say they are working to ensure that the transition bears in mind commercial interests. In some cases, they say, tighter security could even improve the flow of trade.

For example, officials point to a program called Customs-Trade Partnership Against Terrorism that offers companies faster clearance at U.S. borders if they invest in better security all along the supply chain. Another program, the Container Security Initiative, expedites processing at U.S. ports for ship containers that are screened at foreign seaports.

"We have to be sensitive to this important balance of security and facilitation of trade," said Jimmy Gurule, the top enforcement official at the Treasury Department.