People won't be able to start filing taxes until Feb. 12, the Internal Revenue Service (IRS) said on Jan. 15.
The delay will give the agency time to do additional programming and testing of systems following tax law changes implemented late last year.
The changes were made to give most Americans another round of direct payments after Congress passed a $900 billion COVID-19 relief package.
The IRS needs to do programming to make sure its systems run smoothly, according to the agency.
"If filing season were opened without the correct programming in place, then there could be a delay in issuing refunds to taxpayers. These changes ensure that eligible people will receive any remaining stimulus money as a Recovery Rebate Credit when they file their 2020 tax return," it said in a notice.
While taxpayers can usually start filing returns in January, the start of tax season occasionally has been delayed.
"Planning for the nation's filing season process is a massive undertaking, and IRS teams have been working non-stop to prepare for this as well as delivering Economic Impact Payments in record time," IRS Commissioner Chuck Rettig said in a statement.
"Given the pandemic, this is one of the nation's most important filing seasons ever. This start date will ensure that people get their needed tax refunds quickly while also making sure they receive any remaining stimulus payments they are eligible for as quickly as possible."
Americans who want refunds as soon as possible should file electronically with direct deposit. After filing, they can check the IRS tool "Where's My Refund" to find out when their refund is due.
The IRS expects that 90 percent of taxpayers will receive refunds within 21 days of filing if they file electronically.
"To avoid delays in processing, people should avoid filing paper returns wherever possible," the IRS said.
Last year's average refund was more than $2,500.
House Ways and Means Chairman Richard Neal (D-Mass.) said in a statement that he's disappointed with the delay.
“While I am disappointed that this year’s filing season will begin later than usual, I recognize that the IRS has faced extraordinary challenges throughout the COVID crisis. It’s a relief to know that despite contending with the distribution of two rounds of economic impact payments, facility closures, and other disruptions, the agency will be able to begin accepting returns within the next month," he said.
"It is also encouraging that the IRS expects taxpayers who file electronically at the beginning of the season and claim refundable tax credits to receive their refunds by the first week of March. I urge taxpayers to complete their returns and file electronically as early as possible.”