The House's top watchdog on Wednesday accused Health and Human Services Secretary Kathleen Sebelius of making "false and misleading statements" to Congress about security risks related to the plagued website.

House Oversight and Government Reform Committee Chairman Darrell Issa, R-Calif., has requested documents and communications made in preparation for Sebelius’s congressional appearances after Oct. 1.

Issa hinted that Sebelius could face perjury charges if she doesn't comply.

"Witnesses who purposely give false or misleading testimony during a congressional hearing may be subject to criminal liability," he said in a Wednesday letter to Sebelius. "With that in mind, I write to request that you correct the record and to implore you to be truthful with the American public about matters related to Obamacare going forward."

At the center of Issa's probe is Mitre Corp., a contractor working to assess security issues with the Obamacare website.

Issa says Sebelius wasn't truthful when she suggested to lawmakers that Mitre was conducting ongoing security tests on in the days immediately leading up to the website's October launch.

He added that Sebelius wasn't upfront when she said prior tests by the company didn't show potential red flags with the website.

“Providing false or misleading testimony to Congress is a serious matter," Issa wrote in the letter.

"Your failure during numerous congressional hearings to explicitly mention the serious problems with security testing in the month prior to launch [of the site] creates the appearance that you carefully chose language that would mislead members of Congress and the American public."

Administration officials have said the federal Obamacare portal is safe and hasn't been hacked.