Republicans say fake applications that were approved for Obamacare coverage show systemic problems with the Obama administration's enrollment process.

The Government Accountability Office testified Thursday before a Senate panel about its sting operation in which 11 of 12 fake applications were approved and re-enrolled in Obamacare on the federal healthcare exchanges.

Republicans were outraged, saying that it points to major flaws in program integrity.

"Several applications were approved and then re-approved without submitting documentation to marketplace. How can this be?" asked Sen. John Thune, R-S.D. "These are really troubling results."

Sen. Chuck Grassley, R-Iowa, asked Seto Bagdoyan, the GAO's director of audit services, whether the administration values access over program integrity.

Bagdoyan said it appears the program favors access over integrity but cautioned the investigation is not finished.

The sting started in 2014 when GAO filed 12 false applications for coverage. Of those, 11 got through and received about $30,000 in subsidies.

All 11 applications were automatically re-enrolled in Obamacare without anyone asking for new documentation during the 2015 open enrollment period. The agency did drop coverage for six applications because of missing documentation, but five got their coverage reinstated.

Democrats noted that the watchdog's work isn't done.

The investigation hasn't been able to detect a fraud rate for real enrollees, nor has it uncovered any real individuals receiving fraudulent healthcare coverage, said Sen. Rob Wyden, D-Ore., ranking member of the Senate Finance Committee, which held the hearing.

The agency has not developed full recommendations for the Centers for Medicare and Medicaid Services, which manages the federal exchanges.

"It is clear to me that the auditors have much more work to do before the committee can draw a useful conclusion on this matter," Wyden said.