WASHINGTON — The Bush administration sometimes fails to follow all provisions of laws after President Bush attaches “signing statements” meant to interpret or restrict the legislation, congressional examiners say.

Lawmakers who asked the Government Accountability Office to conduct the study said it was further proof that the Bush White House oversteps constitutional bounds in ignoring the will of Congress.

“Too often, the Bush administration does what it wants, no matter the law. It says what it wants, no matter the facts,” the Senate Appropriations Committee chairman, Senator Byrd, a Democrat of West Virginia, said yesterday. Mr. Byrd and the House Judiciary Committee chairman, Rep. John Conyers, a Democrat of Michigan, requested the report.

Signing statements, in which the president appends bills he is signing into law with statements reserving the right to revise, interpret, or disregard provisions on national security and constitutional grounds, have become a major sticking point in the power struggle between Congress and the White House.

Mr. Conyers made signing statements the topic of his committee’s first oversight hearing after Democrats took over control of Congress in January.

The limited GAO study examined signing statements concerning 19 provisions in fiscal year 2006 spending bills. It found that in six of those cases the provisions were not executed as written.

In one case, the Pentagon did not include separate budget justification documents explaining how the Iraq War funding was to be spent in its 2007 budget request. In another, the Federal Emergency Management Agency did not submit a proposal and spending plan for housing, as Congress directed.

The White House, in issuing the statements, has argued that the president has a right to control executive branch employees and officers, that he has authority to withhold from Congress information sometimes considered privileged or that Congress should not interfere with his constitutional role as commander in chief.

The GAO report, which did not assess the merits of the president’s arguments, said signing statements go back at least to President Jackson, while citing other congressional studies that such statements have become increasingly common since the Reagan administration.

Messrs. Byrd and Conyers said Mr. Bush has issued 149 signing statements, 127 of which raised some objection. They said the statements often raise multiple objections, resulting in more than 700 challenges to distinct provisions of law.

The GAO said signing statements accompanied 11 of the 12 spending bills in 2006, singling out 160 specific provisions in those bills.

The issue gained attention last year after Mr. Bush — after lengthy negotiations on renewal of the Patriot Act with language backed by Senator McCain, a Republican of Arizona, that banned the torture of detainees — attached a signing statement in which he reserved the right to interpret that provision.

The White House has defended the statements, saying presidents have always defended their prerogatives when it comes to national security and it is important to express reservations about the constitutionality of legislation.

The American Bar Association, at an annual meeting last year, approved a resolution condemning use of signing statements, saying presidents should not resort to diluting or changing laws passed by Congress rather than using their veto powers.