WASHINGTON — Undercover investigators using fake identities were able to secure taxpayer-subsidized health insurance under President Obama’s health care law, congressional investigators said Wednesday.

The weak link seemed to be call centers that handled applications for frazzled consumers unable to get through online.

The nonpartisan Government Accountability Office told a House committee that its investigators were able to get subsidized health care under fake names in 11 out of 18 attempts – even after HealthCare.gov‘s much maligned online system flagged some applications as problematic.

The GAO is still paying premiums for the policies, even as the Obama administration attempts to verify phony documentation.

Those follow-up verification checks also appeared to need tightening; the GAO said parts of the fake documentation it submitted for two applications actually got through the process.

Nonetheless, GAO audits and investigations chief Seto Bagdoyan told the House Ways and Means Committee that the agency has not drawn any sweeping conclusions from what he called its “preliminary” findings. A full assessment will take several months.

In the real world, it may be difficult for fraud artists to profit from the nation’s newest social program, since government health care subsidies are paid directly to insurance companies.

Still, GAO’s report opened another line of attack for Republican lawmakers who have relentlessly tried to kill the 2010 Affordable Care Act. It raised questions about new sorts of flaws in the enrollment system, which experienced computer gridlock when it went live last fall. Ultimately, 8 million people managed to sign up for subsidized health care in federal and state exchanges that handled “Obamacare” enrollment.

GAO also testified that there’s still a huge backlog of applications with data discrepancies, even though the administration has resolved some 600,000 cases.

Rep. Charles Boustany, R-La., said the findings point to more bungling by the Obama administration. “This is simply not a question of whether one likes the administration’s health care law; it’s a question of being good stewards of taxpayer dollars,” he said.

Speaking for committee Democrats, Rep. John Lewis of Georgia said it’s time for Republicans to stop trying to dismantle the health care law and instead start fixing problems. “We will not go back to a time when Americans did not have access to affordable health insurance,” said Lewis.

The Obama administration is taking the report seriously.