Adding his voice to the growing chorus of lawmakers calling for Health and Human Services Secretary Kathleen Sebelius to step down in the wake of Obamacare's clunky rollout, Rep. Darrell Issa on Sunday questioned why she continues to stay on.

"The president has been poorly served in the implementation of his own legislation," Issa, R-Calif., said in an interview on "Face The Nation" on CBS. "If somebody doesn't leave ... then he's missing the point of Management 101, which is these people are there to serve him well, and they haven't."

Issa called on Sebelius to step down voluntarily.

Earlier this week, 32 House Republicans wrote to the president calling for Sebelius to resign. Issa was not among them.

And, in the Senate, a group of Democrats has begun calling for an extension of the Obamacare sign-up deadline to give people required to have insurance more time to get it since early attempts to use the online sign-up failed for most of them.

"The rollout has been a disaster," said Sen. Jeanne Shaheen, D-N.H., one of the lawmakers who supports a delay.