"We have the cruise line industry out there (in Honolulu Harbor), possibly the superferry in that area in two-three years, and along with that the cargo industry," said state Department of Transportation spokesman Scott Ishikawa. "So if we can move some of that shipping to Kalaeloa it would open up space in Honolulu Harbor."

Kalaeloa is the second-busiest harbor in Hawai'i.

The discount on the wharfage rate, imposed on cargo unloaded at piers in state harbors, would start this year with a 50 percent reduction off the original rate.

The amount of the discount would decrease by 10 percent every year and in 2010 the rate would revert back to the current level.

That means wharfage fees for lumber and general merchandise from the Mainland, now $2.12 per ton, would be reduced to $1.06 through the end of this year. By 2009 the rate would be $1.91 per ton, and the original rate would be restored the following year.

The discount applies to incoming and outgoing domestic and foreign overseas cargo, as well as interisland cargo.

Kraig Kennedy, head of the maritime committee for the Chamber of Commerce of Hawai'i, said it's hard to tell at this point what kind of impact the discount may have. He said it would likely be more expensive for some companies to operate out of Kalaeloa, but that the idea may be a good step in relieving traffic at Honolulu Harbor.

"We're all looking for ways to try to deal with the increases in cargo traffic coming into Honolulu over the last few years," he said. "We've gotta do something, so I'm not adverse to looking at anything that might help the situation. And that might be one of the ways that would help."

State Department of Transportation deputy director Barry Fukunaga said he is not aware of any companies that have expressed interest in transferring operations to Kalaeloa.

Cargo carrier Sause Brothers moved its operations to Kalaeloa last year.

Major shipping companies have said they are running out of cargo space at Honolulu Harbor and that they want the state to expedite plans to convert the Kapalama Military Reservation off Sand Island Road into a cargo terminal. State officials have said they're trying to speed up the Kapalama project to get it done by 2011, two years earlier than originally planned.

Maritime industry representatives, as well as transportation officials, say that Kalaeloa harbor is 35 feet deep and would need to be dredged to a depth of 42 feet to accommodate larger cargo ships.