Kristi Noem, the homeland security secretary, defended the federal government’s response on Sunday to catastrophic flooding in Texas that left more than 120 dead. She dismissed as “absolutely false” reports that recent policy changes slowed the deployment of critical disaster aid.

In an appearance on NBC’s “Meet the Press,” Ms. Noem denied that a new policy requiring her personal approval for contracts larger than $100,000 had left Federal Emergency Management Agency call centers understaffed for days after floodwaters swept through Texas’s Hill Country on July 4 and 5. The New York Times reported that on July 6 and 7, thousands of calls to the agency went unanswered because hundreds of contractors had been fired when their contracts lapsed on July 5.

“False reporting, fake news,” Ms. Noem said.

Experts and current and former FEMA employees have said the agency was slow to deploy response and search-and-rescue coordination teams. But Ms. Noem insisted that FEMA, which is a part of the Department of Homeland Security, had responded to the Texas flooding better than it had to any other disaster in “many, many years” and dismissed claims to the contrary as attacks by the Trump administration’s political opponents.

“What is really unfortunate is we have a situation where so many individuals are playing politics with what happened to Texas,” she said.