The Obama administration said on Friday that 800,000 people who signed up for health insurance under the Affordable Care Act received incorrect tax forms and should wait to receive new ones before filing their taxes.
Roughly 95 percent of those who received the erroneous 1095-A forms have yet to file taxes, officials said. New forms will be issued in early March.
The Treasury Department said it is weighing what to do about people who have already filed and will provide additional information "shortly."
Republican lawmakers pounced on the mistake.
"The White House tells us in a classic Friday news dump that nearly one million Americans could see their tax refunds delayed because of this president's inability to implement his own law," Tennessee Representative Diane Black said in a statement.
White House spokesman Josh Earnest said the glitch should have no impact on the ability of people to file their taxes by the April 15 deadline. He also said the issue affects "less than 1 percent of people who file taxes."
The administration also said it would extend a special enrollment period for tax filers who were unaware they could face penalties for missing the Feb. 15 deadline to obtain health insurance through the federal marketplace at HealthCare.gov.
The one-off special enrollment period will be extended from March 15 to April 30. If consumers do not buy health insurance during this period, they will have to pay a penalty when they file their 2015 taxes. Eligible filers must live in one of the 37 states with a federally facilitated insurance marketplace.
State-based insurance exchanges can set their own policies, officials said.
To qualify for the special enrollment, consumers must attest that when they filed their 2014 tax return they paid the fee for not having health coverage that year and that they first became aware of the implications of not enrolling in a timely manner after they began preparing their 2014 taxes.
The IRS has estimated 2 percent to 4 percent of tax filers, or roughly six million people, may pay a fee for not having coverage in 2014, which is $95 or 1 percent of income.
The fee increases to $325 per adult or 2 percent of income for 2015. Those who enroll during the special period will still owe fees for the months they were uninsured in 2014 and 2015. The special period is to allow people to avoid additional fees for 2015.
