The Defense Department has signed contracts worth almost $1 million with a private company to maintain U.S. facilities and feed U.S. troops in Honduras, and a Democratic senator said this suggests plans for a longer-term U.S. presence than the Pentagon has acknowledged.

Harbert International Inc. of Birmingham was hired Aug. 1 to feed troops, cut grass, repair plumbing, collect trash, purify water, lease and maintain dozens of cars and trucks and perform other duties for U.S. personnel at Palmerola Air Base "and outlying areas in Honduras," according to contract documents obtained by The Washington Post. The contracts last through 1984, with an option to renew for another nine months.

The Pentagon frequently contracts out for such "base support" at permanent facilities, but Palmerola is a Honduran-owned base where the administration has said U.S. troops are deployed only temporarily on exercises. Troops on exercises normally provide their own food and other support, military officials said.

Sen. Jim Sasser (D-Tenn.), ranking Democrat on the military construction subcommittee of the Senate Appropriations Committee, said yesterday that he was investigating the Harbert contracts, which he said were "most unusual." He said the Pentagon might be contracting out jobs that soldiers ordinarily would do "to artificially lower the number of U.S. military personnel in Honduras."

"The number of U.S. troops in the area does not accurately reflect the level of U.S. involvement," Sasser said.

The senator, speaking by telephone from Tennessee, also said he believes that the maintenance contracts demonstrate that the U.S. Southern Command is not just conducting temporary exercises in Honduras, despite administration claims.

"My clear impression is that when you have a temporary base being used for exercises, you don't enter into long-term contracts with U.S. vendors to collect the garbage and clean the latrines and maintain vehicles," he said. "Base support is being handled the same way it would at permanent bases inside the U.S., not as it would be provided in a makeshift situation during temporary exercises . . . . This again demonstrates the long-term nature of our involvement in Central America."

The Pentagon denied that the contract is unusual.

"This type of support contract is common in many areas of the world," a spokesman said. "It reduces the impact on the CONUS continental United States home bases during temporary deployments by allowing many of the support personnel to remain behind in CONUS."

Claude Roberts, manager of government services for Harbert, declined to say how many employes the company has in Honduras. Harbert has a $560,000 contract for maintenance and food services and a $404,000 contract to lease and maintain about 40 cars and trucks in Palmerola, with both sums covering the period from Aug. 1 to Dec. 31.

Asked how long Harbert would work in Honduras, Roberts joked, "I hope forever." He noted that the government could extend the contract through next September and could renew it beyond that.

"This is not unusual, I am told," Roberts said. "I don't get into the politics of the thing . . . . I can only assume it's probably cheaper, and I think everybody's watching the dollar."

Harbert is primarily an engineering and construction company that has built pipelines and other facilities in South America and Egypt. Roberts said the company gained experience maintaining base camps while supporting its own construction workers in Egypt and, for a time, supporting the multinational peace-keeping force in Egypt's Sinai Peninsula.

The original maintenance contract, signed in July, allotted $223,000. That amount was increased in two amendments, most recently in September, that tripled the amount of water Harbert must distribute from 10,000 gallons to 30,000 gallons a day and added "outlying areas in Honduras" to the company's responsibilities.

The Pentagon has said that from 700 to 1,000 troops have been in Honduras since large-scale exercises ended last spring. Defense Secretary Caspar W. Weinberger told Congress that the troops remained to guard equipment between major maneuvers, which are expected to resume.

Other officials have said that some of the troops are operating radar facilities, flying reconnaissance planes and performing other missions in support of neighboring El Salvador against leftist rebels.

The maintenance contract also calls for Harbert to do laundry, provide electricians, maintain roads and run the showers.