WASHINGTON -- Congress could avoid controversy involving billions of dollars in secret defense spending by shedding at least a little more light on classified, or "black," budgets, experts said Tuesday.

The secrecy leads frequently to questions, as it has this week when it was reported that a friend and campaign contributor to Rep. Jim Gibbons, R-Nev., landed classified contracts with help from the lawmaker.

One analyst who has campaigned for more openness said tighter rules might have saved Gibbons from criticism.

"It should not be permissible to receive lobbying funds from black budget recipients. That would single-handedly eliminate the questions in the Gibbons case," said Steven Aftergood, director of the Project on Government Secrecy at the Federation of American Scientists.

The federal government is expected to spend more than $30 billion this fiscal year on secret defense and intelligence programs, many labeled by code words and known only to select lawmakers and staffers.

Gibbons used his position to help the Reno software firm owned by Warren Trepp score millions of dollars in contracts, according to a Wall Street Journal article.

Gibbons denied acting inappropriately.

Aftergood said lawmakers can balance a need for national security with appropriate oversight by at least indicating the total amount spent on intelligence. He added that such a disclosure was a recommendation from the 9-11 Commission.

He said contractors should be forced to choose whether to accept secret government contracts or donate to lawmakers, but not both.

Former Rep. Randy "Duke" Cunningham, R-Calif., resigned last year after pleading guilty to taking $2 million in bribes from defense contractors who received classified contracts.

John Pike, a defense analyst for the Web site globalsecurity.org, said the Cunningham case demonstrated how easily black budgets can be abused.

"The problem is, there are a series of feedback mechanisms you have for normal program oversight," such as the Government Accountability Office and news organizations, he said.

"Normally, someone will figure it out before it goes into the ditch," Pike said.

Not so for secret programs, he said.

The Center for Strategic and Budgetary Assessments estimated the fiscal 2007 defense budget included $30.1 billion for classified programs. In the past, black budgets were used for research, development and purchase of the F-117 stealth fighter and the B-2 stealth bomber.

The Air Force takes the largest share of black budget money, about 75 percent. The Air Force budget funds several intelligence programs.

Funding is authorized by armed services and intelligence committees and appropriated by the defense subcommittees of the House and Senate appropriations committees.

Aftergood said only a few of the appropriations subcommittee members are aware of the specific projects funded.

"You've got tens of billions of dollars divvied up among tens of members and staffers, and you're not going to get much oversight per dollar," he said. "It's easy for questionable items to slip through or be pushed through."

Steven Kosiak, who determined the black budget figures for the Center for Strategic and Budgetary Adjustments, said he tracked the money generally by subtracting unclassified budget amounts from the total Department of Defense budget.

He said the Pentagon determines what should be classified, and a handful of lawmakers are briefed on the items, with congressional oversight based on the type of spending.

Pike described the process as "highly fragmented."

"I assume these programs are on the up and up and are all run by patriotic, loyal Americans, but if that was not the case, it would be hard to find out," Pike said.