LOS ANGELES » Negotiators returned to the bargaining table Monday as a strike that has crippled operations at the nation’s largest port complex entered its seventh day.

Los Angeles Mayor Antonio Villaraigosa demanded that both sides meet nonstop until they reach an agreement.

"It seems like progress is being made," union spokes­man Craig Merrilees said after negotiations resumed. "It’s not quick and it’s not easy, but there is some progress."

Management spokes­man Steve Getzug was less optimistic, saying union negotiators were resisting proposed changes in hiring practices that he said would give shippers the ability to avoid hiring unneeded employees. It’s a practice management dismisses as featherbedding.

"Rather than having artificial staffing levels, we’re saying give us the ability to make decisions based on need, and we think that’s a reasonable request," Getzug said.

Union members counter that the issue involves management’s desire to outsource jobs to places such as Taiwan and China, where shippers can pay lower wages for work that can be done on computer.

"It’s important to us to keep those jobs here in the United States. We’re fighting against corporate greed," Merrilees said.

Since the strike began Nov. 27, it has idled operations at 10 of the 14 terminals at the port complex, bringing to a standstill three-quarters of the estimated $1 billion a day in cargo that moves through the nation’s busiest shipping complex.

Experts say it is also idling thousands of truck drivers and, if it continues, threatens to create shortages for wholesalers and retailers around the country.

(Matson and Horizon Lines, the two ocean shippers that service Hawaii from that port complex, say they have been unaffected by the shutdown.)

Villaraigosa sent a letter to both sides Sunday demanding that they call in a mediator and negotiate nonstop until they reach an agreement.

"If there’s no negotiating progress in the next day, I would assume there will be calls for the president to get involved and invoke the Taft-Hartley Act and get people back to work," said Kristin Monaco, an economics professor at California State University, Long Beach, and an expert on port and trucking industry labor issues.

Former President George W. Bush invoked the act in 2002 to end a 10-day dockworkers lockout that had spread across the entire West Coast.

The International Longshore and Warehouse Union’s clerical workers local represents about 600 clerks at the two ports, However, unionized dockworkers, who number about 10,000, are refusing to cross the picket lines to load and unload cargo.

Both sides agree that salaries, vacation and pension benefits for current employees are not an issue in the negotiations.

The union says average clerical salaries are $41 an hour, or about $87,000 a year. When benefits are factored in, that raises annual compensation to $165,000, Getzug said.

He added that management has offered a new contract that would raise that amount to about $195,000 by 2016, along with providing 11 weeks of vacation.

"We know we’re blessed," port clerk Trinnie Thompson said by phone as she walked the picket line outside one of the terminals. "We’re very thankful for our jobs. We just want to keep them."