LOS ANGELES -- American businesses have weathered the first week of the West Coast port lockout, but conditions may begin deteriorating if a settlement is not reached during weekend negotiations.

Household names in U.S. manufacturing may run out of parts and be forced to shut down their assembly lines in the next few days, said Darren McKinney, spokesman for the National Association of Manufacturers.

"They are running up against the wall very quickly," he said.

And even if the port shutdown ends soon, many U.S. factories may have to shut down anyway because the parts they need will be caught in a huge backlog of cargo.

"The challenge is going to be the chaos and bedlam on the water as they try to pull things out," said Michael Damer, spokesman for New United Motor Manufacturing, which idled its plant near the Port of Oakland on Wednesday, halting the assembly of Toyota and Pontiac cars and trucks.

Nissan and Boeing were among the biggest companies feeling the pinch from the shutdown that began Sunday at the nation's 29 West Coast ports in Washington, Oregon and California.

The Pacific Maritime Association, which represents shipping companies and terminal operators, locked out 10,500 members of the longshoremen's union, claiming the dockworkers had engaged in a slowdown. The main issue is whether jobs created by new technology will be unionized.

The shutdown is costing the U.S. economy an estimated $2 billion a day.

Nissan North America plans to eliminate the Saturday shift at its Smyrna, Tenn., plant that manufactures nearly 500,000 Altimas, Xterra SUVs and Frontier pickups a year and will soon shut down entirely if the lockout doesn't end.

"We can probably make it to the end of next week, but beyond that we'd probably have to shut the plant down," spokesman Scott Vasin said.

Boeing Co., the world's largest commercial airplane manufacturer, could also see its production pinched as soon as next week.

With fuselage parts sitting in container ships waiting to be unloaded at the ports of Seattle and Tacoma, the company will have to build its jets "out of sequence," adding to costs and delaying production, said Boeing spokesman Peter Conte.

In other developments, the Pacific Maritime Association granted Hawaii an exemption from the West Coast port lockout. The process of unloading ships was expected to begin Saturday in Hawaii, which imports 90 percent of its goods.

"This is good news for the people of Hawaii," Gov. Ben Cayetano said Friday night.

Meanwhile, air cargo rates have climbed by as much as 30 percent since Sunday, as the lockout coincides with the seasonal increase in shipments, placing a premium on available capacity.

With almost 200 ships laden with Asian cargo left waiting along the coast, the shutdown was also having a domino effect throughout the economy.

Union Pacific, the nation's largest railroad, had 55 trains parked across the western United States, unable to move cargo. Grain shipments bound for export were sitting in warehouses and growers of perishable goods like apples and citrus worried that their harvests would not reach lucrative Asian markets.

Representatives of dockworkers and management were expected to meet with a federal mediator for a third consecutive day Saturday. On Friday, the parties spent the entire day trying to reach a new contract, while business groups pushed for government intervention in a meeting with White House officials.

The meat and poultry industry, which ships more than $5 billion worth of products to Asia each year, called on Bush to use his authority to end the labor disruption.

An administration official said the White House position remained unchanged, with Bush closely monitoring the situation and urging both sides to work with federal mediators.

Labor Secretary Elaine Chao and the governors of California, Oregon and Washington joined a long list of politicians urging the parties to reach an agreement swiftly.

The PMA did agree to hire longshoremen to load Alaska-bound cargo ships at the Port of Tacoma, and on Friday longshoremen were loading Totem Ocean Trailer Express and CSX Lines with groceries, household goods and other products.

The two sides agreed to the exception because of Alaska's dependence on cargo from the port. They also agreed to allow six workers in Oakland and Concord to move some military cargo on the docks Saturday.

Industries most at risk of supply problems during the lockout are automotive, clothing, toy manufacturing, food, agriculture and electronics.

By SIMON AVERY, AP Business Writer