As Congress spars over a stimulus bill, health care plans and budget cuts, the flurry of work is increasing the cost of running the legislative branch.

Congress’ own budget accounts for a very small piece of the omnibus pie — about $4.4 billion of the total $410 billion — but it’s always a sensitive topic.

Every rise in staff salary and every increase in office expenses is another dollar Congress is spending on itself, and in times of economic turmoil, appropriators are wary of increasing budgets.

But this year, the legislative branch would get an 11 percent increase in the fiscal 2009 omnibus package that passed the House last week — far more than the 3 percent hike it received for fiscal 2008.

Part of that increase is due to a large boost in the budgets of the Government Accountability Office and the Congressional Budget Office, two agencies that prepare reports and cost estimates to Members.

As the watchdog of Congress, the GAO prepares in-depth reports for every committee on topics ranging from defense to health care to infrastructure.

In the past two years, requests for these reports have increased dramatically, and yet the agency’s staffing levels are the lowest in its history. Analysts are so overburdened that a new request can sit around for four months before someone has the time to address it.

GAO officials worry that the crush of work will only get worse under an administration intent on restructuring several areas of the government and a Congress sharply split over how to handle it all.

Under the omnibus, the agency would get $531 million, a more than 6 percent increase in its budget.

“We’re very pleased that the Congress has [accepted] our request and recognized that we needed it,” Acting Comptroller General Gene Dodaro said last week. “We expect that demand for our services will remain high and will likely increase.”

A similar situation exists at the CBO, where about 230 full-time experts produce cost estimates on every major piece of legislation — and one on every minor bill that a committee requests.

Under the new Troubled Assets Relief Program, the agency also took on the mammoth task of reviewing the assets purchased by the government. That means the CBO has to hire new experts — financial analysts who know the ins and outs of the banking world.

The agency is set to receive $44 million, an 18 percent increase from fiscal 2008 and $1.3 million more than it originally requested. Officials hope the money will enable them to hire 15 new employees, partly to help on the expected flurry of requests for health care proposals.

But these increases only account for some of the ballooned legislative branch budget. Other new spending includes $29 million to update digital books for the blind; $4 million to increase student loan repayment and transit benefits for staffers; and $248 million for the salaries of almost 1,800 Capitol Police officers.

Members also got a hefty increase in their office budgets, which officials say is due to an economic crisis that has increased constituent needs.

In the House, that meant an increase of almost $30 million, meaning roughly $68,000 more for each office to spend on salaries, travel and mailings. In the Senate, the increase was about 7 percent, rising from a total of about $374 million to $400 million.

In January, House Administration Committee spokesman Kyle Anderson justified the House increase as necessary to “allow Members’ offices to continue to effectively serve their constituents during this difficult period.”

“Failure to address these rising expenses could result in resources having to be diverted from key areas such as constituent service and Member outreach,” he said.

But some of the largest increases in the legislative branch budget are unrelated to the dreary economic outlook and Congress’ legislative hustling — mainly, the Capitol complex’s crumbling infrastructure.

The Architect of the Capitol has estimated that the Capitol and Congressional office buildings need $1.4 billion in maintenance work and renewal projects, but every year, many of those repairs are delayed to keep costs down. This year, Congress approved hundreds of millions of dollars to begin the process.

Chief among those costs is repairs to the utility tunnels that run underneath the Capitol, providing heating and cooling to Congressional buildings. Two years ago, the Architect of the Capitol entered an agreement with the Office of Compliance to fix crumbling concrete walls, unusable communication systems and pipes covered in exposed asbestos.

All in all, it will cost $300 million to fix all the short-term problems outlined in the agreement; long-term improvements will commence after 2012.

The omnibus provides $56 million for some of those improvements, $70 million less than the Architect originally requested.

It’s unclear why less money was needed. AOC spokeswoman Eva Malecki declined to give specifics, instead referring to the implementation of “alternative engineering methods” and “innovative new construction technologies.”

“Based on the excellent progress being made during ongoing engineering work,” she wrote in an e-mail, “we have evaluated and re-validated our approach to the project work to improve the utility tunnels and have refined our budget projection accordingly.”

The AOC’s almost $530 million budget also includes appropriations for a smoke control system in the Capitol, egress improvements in the Longworth House Office Building and the last $31 million for the final touches on the $621 million Capitol Visitor Center.