A couple of prominent Republicans in the U.S. Senate attacked the White House on Sunday over Obamacare, criticizing Health and Human Services Secretary Kathleen Sebelius.

Sens. Marco Rubio and Roy Blunt, of Florida and Missouri, respectively, told “Fox News Sunday” viewers they wanted the embattled secretary to testify before Congress about continued problems in implementing online healthcare exchanges as part of the Affordable Care Act.

While other Republicans in Congress have called for Sebelius’ resignation, Rubio said he wanted her to testify at a hearing. “I think [resignation] may become an option,” he said when asked if President Obama should replace her. “I’m not a big fan of media calls for people to resign but I think, in this case, actions like the one you just outlined will make it harder and harder for her to do her job.”

Rubio criticized Sebelius for refusing to testify before Congress about technological problems with opening healthcare exchanges. “Her refusal to testify and be transparent about it, I think, is undermining her credibility. And there may come a point now, perhaps we’re not there today, where she will have to resign.”

Blunt also said Sebelius should testify. “The secretary’s view that she doesn’t have to testify, doesn’t have to answer questions, that she’s too busy for that, is unsustainable,” he said on Sunday. “I think she’ll have to testify. I don’t think she can refuse to answer questions about this and try to defend that ‘I have time to go to a gala in Boston, but I don’t have the time to appear before the Congress because I’m so busy trying to make this system work.’”

Likewise, Senate Minority Whip Dick Durban, a Democrat from Illinois, predicted Sebelius would eventually succumb to pressure to testify. "Ultimately, Secretary Sebelius will testify before Congress," he said, also appearing on "Fox News Sunday." "You know that. I don't know the circumstances behind this, last-minute, let's do it in a few days."

The U.S. House Commerce Committee plans to hold a hearing on the matter Wednesday.