Hundreds of thousands of Americans who signed up for President Barack Obama’s mandated health care programme have received incorrect tax information.
Nearly 800,000 customers were asked on Friday to delay filing their 2014 tax returns after the Obama administration recognised the mistake.
Officials said the tax forms contained a health insurance subsidy error that could cause some people to receive greater or lesser refunds than they are entitled to under the Affordable Care Act (ACA).
The error is the latest in a series of woes the President’s signature health care legislation has encountered since it was signed into law in 2010.
The administration also announced on Friday it would open a special enrolment period for tax filers who were unaware they could face a tax penalty if they did not sign up by the 15 February deadline.
Several million households could benefit from that grace period, which will run from 15 March to 30 April.
Under the programme, dubbed Obamacare, Americans who do not have employer-based coverage must enrol in an ACA-approved plan or pay a tax penalty.
The minimum penalty in 2015 will be $325 per person or up to 2% of annual income.
Republicans have long opposed Obamacare as an example of government overreach.
The GOP-controlled House has voted to repeal the law 56 times since its enactment, but it never made it through the Senate.
Even if a veto were to pass both chambers, now under Republican control, Mr Obama would certainly veto the measure.
The Supreme Court, meanwhile, will hear a case this spring challenging the government subsidies, which are provided to low-income Americans to help reduce the costs of the mandated insurance plans.
The legal challenge maintains that financial aid can only be provided in states that have set up their own health insurance coverages but not in states using the federal exchanges.