WASHINGTON (CNN) -- A post-9/11 law that sets federal standards for state driver's licenses and identification cards is under fire from the head of the agency enforcing that law, the Department of Homeland Security.

Homeland Security chief Janet Napolitano, here last week in San Pedro, California, wants to replace the Real ID.

Homeland Security Secretary Janet Napolitano this week said she is working with governors to repeal the Real ID Act, which was passed in 2005 and went into effect last year.

The bill is popular in Washington, but is scorned by many governors who bear the responsibility and cost of validating that holders of driver's licenses are citizens or legal residents of the United States.

Napolitano, former governor of Arizona, said she has met with governors of both parties recently "to look at a way to repeal Real ID." She said she wants to substitute the federal law with "something else that pivots off of the driver's license but accomplishes some of the same goals. And we hope to be able to announce something on that fairly soon."

Napolitano made her remarks Tuesday in response to a question at a conference of the Anti-Defamation League.

On Wednesday, Rep. James Sensenbrenner, R-Wisconsin, a sponsor of the law, said he was "angered" by Napolitano's comments.

"Real ID is a necessary program for keeping America safe. It is the will of Congress and also a recommendation of the 9/11 Commission," Sensenbrenner said.

"When the Democrats took over the majority in the 110th Congress, they said they wanted to implement all of the 9/11 Commission recommendations. I am highly disappointed that they are going back on their word by repealing this important recommendation, and substituting it with a weaker, less safe program that provides terrorists with too many avenues to attack."

While Napolitano is looking for ways to repeal Real ID, her department's Web site continues to espouse the law's merits.

"Raising the standards of state-issued identification is an important step toward enhancing national security," the Web site says.

"Because a driver's license serves so many purposes [access to federal buildings, nuclear power plants, boarding aircraft, etc.], terrorists actively seek fraudulent state-issued identification. The Real ID rules will make it more difficult for them, while making it easier for law enforcement to detect falsified documents," it says.

The law, which requires all states to enforce specific identification requirements for driver's licenses and identification cards, went into effect last year, but the federal government has given states until the end of this year to implement it. States can get extensions until May 2011 for implementation if they meet certain benchmarks.

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