WASHINGTON — The Government Accountability Office on Tuesday added the Postal Service to its list of high-risk federal agencies in need of change.

The post office has been struggling with a sharp decline in mail volume as people and businesses switch to e-mail both for personal contact and bill paying. The agency is facing a nearly $7 billion potential loss this fiscal year despite a 2-cent increase in the price of stamps in May and cuts in staff.

"There are serious and significant structural financial challenges currently facing the Postal Service," the GAO said.

"New technology is profoundly affecting services in both the private and public sectors, including traditional mail delivery. Compounded by the current recession, the volume of mail being sent is dropping substantially," Gene L. Dodaro, acting comptroller general, said in a statement.

The report called on the Postal Service to work with Congress and other organizations to develop and implement a restructuring plan.

The post office issued a statement saying: "The GAO High Risk List announcement accurately reflects our current financial reality. Securing the fiscal stability of the Postal Service will require continued review of retiree health benefit prefunding, as well as gaining flexibility within the law to move toward five-day delivery, to adjust our network as needed, to develop new products the market requires and to work with our unions, mailers, stakeholders and Congress to meet the challenges ahead."

The Mailers Council, which represents businesses and organizations that mail large volumes of material, supported GAO's action.

Pending legislation in the House and Senate would offer short-term help, but "that can only postpone the inevitable insolvency of the Postal Service. We firmly believe the Postal Service will be unable to meet its financial obligations in the near future without fundamental structural change," council executive director Robert C. McLean said.

He said "every major postal policy, from employee pay, to days of delivery, to the closing of postal facilities must be on the table. Without major change, the day will soon come when the Postal Service will be unable to pay its bills. ..."

Last year, mail volume fell by 9.5 billion pieces to a total of 203 billion pieces.