Washington, September 16 (RHC)-- A change in U.S. government procedures has led to a major increase in immigrants losing health insurance under President Barack Obama’s healthcare law because of immigration and citizenship issues.

More than 400,000 people in the U.S., mostly immigrants, have had their health coverage canceled so far in 2015, nearly four times as many as last year, the Associated Press reported Saturday. Obama's healthcare law specifies that only U.S. citizens and legal residents are eligible for coverage through the new insurance markets that provide subsidized coverage.

Advocates say the high number of terminations is because the Obama administration's system for verifying insurance eligibility is seriously flawed. The majority of the 423,000 people whose coverage was canceled are legal U.S. citizens and residents stuck in a complicated, inefficient system for checking citizenship and residency documents, according to the National Immigration Law Center, an advocacy group in Washington, DC.

It defies common sense that many immigrants without legal documents to be in the US would risk alerting a federal agency by applying for taxpayer-subsidized health benefits, said Angel Padilla, the National Immigration Law Center's health policy analyst.

However, the number of coverage terminations could actually be higher, according to the AP. The 423,000 figure only represents states served by the federal health insurance market. That does not include states like California and New York with high numbers of immigrants that run their own insurance exchanges.