Washington ? The White House threatened to veto legislation approved by a Senate committee Thursday that creates a mammoth Homeland Security Department, contending President Bush would have little power to react quickly to terrorist threats.

The bill, written largely by Senate Democrats, does not include the flexibility that Bush wants over managers and employees at the 170,000-worker Cabinet agency, White House spokesman Ari Fleischer said. As a result, Bush advisers would recommend a veto, he said.

The president reinforced that message in a speech in High Point, N.C.

“I just want to make sure that Congress understands that when we do this department, I’ve got to have the ability to manage the department in a way to make the homeland more secure,” Bush said.

The Senate Governmental Affairs Committee passed the bill by a 12-5 vote. The House opened debate Thursday night, with a final vote planned today on most amendments and the main bill.

Despite broad support overall for the plan, some House members worried about chaos during the agency’s start-up. They said staffing and money problems would not disappear with the transfer of 22 government entities into the new department.

Sen. Mark Dayton, D-Minn., said the president’s plan amounted to “a blank check to hire, fire, sanction, whatever, individual employees.”

Republicans say a department dedicated to tracking a shadowy enemy and preventing terrorist attacks should not be shackled by burdensome rules.