WASHINGTON – The former head of the Federal Emergency Management Agency, Michael Brown, deliberately ignored a new national disaster plan and circumvented his boss, the homeland security secretary, Michael Chertoff, in trying to manage the federal response to Hurricane Katrina directly with the White House, according to a new House report.

By disregarding the National Response Plan, finished in 2004, Mr. Brown deprived “the nation of an opportunity to determine whether the NRP worked,” the House investigation concludes in an addendum to its February 15 report, “A Failure of Initiative,” scheduled for release today.

The all-Republican panel, led by Chairman Tom Davis, a Republican of Virginia, prepared the supplement after issuing a subpoena and obtaining Mr. Brown’s sworn deposition February 11, too late to publish in its scathing 520-page study.

By attributing numerous failings to Mr. Brown, the new House report obtained by the Washington Post refocuses an unflattering spotlight on the former Bush political loyalist and on the White House. Though he resigned under fire for his handling of the hurricane response, Mr. Brown’s image was rehabilitated somewhat in videos leaked this month that showed him imploring the government to gear up for Katrina and emphatically warning the White House.

But the House reported that Mr. Brown “virtually boasted” that he avoided communicating with Mr. Chertoff – then in office about six months – “and called directly on the White House for assistance instead.” Mr. Brown opposed or never advised the new secretary to take steps under the response plan, such as declaring an “incident of national significance,” activating a Catastrophic Incident Annex to speed federal aid, convening an expert Interagency Incident Management Group, or naming a principal federal officer in charge, the report said.

“We’ll need to keep that in mind as Congress considers its post-Katrina agenda,” Mr. Davis said in a statement. “FEMA needs serious work, but the NRP might not.”

The additional report comes as House committees debate post-storm homeland security changes and a separate Senate investigation wraps up its work. The Bush administration also has issued a report with 125 recommendations.

Among other issues, the House report noted, “Brown’s communications with the White House … raise serious questions about when and how the White House becomes involved in disaster response.”

Yesterday, the Senate investigation chairwoman, Susan Collins, a Republican of Maine, denied a request by ranking member Senator Lieberman, a Democrat of Connecticut, to subpoena documents and testimony from Bush aides.

“Virtually everyone in the White House who had anything of operational significance to do with” Katrina has been “put off limits,” he wrote. “This has left us unable to obtain any real sense of what the White House did or didn’t do.” Mr. Lieberman said a Congressional Research Service review found 75 cases in which top presidential aides – including chiefs of staff, White House counsel, and National Security advisors – testified to legislative investigators since 1926.

Ms. Collins called Mr. Lieberman’s request “neither warranted nor appropriate,” because it could deprive presidents of candid advice and violate executive privilege. She said aides have provided three briefings and 23,300 pages of documents.