(CNN) - Hundreds of Internal Revenue Service workers dealing with financial hardship were given permission to miss work during the partial government shutdown, which could slow the federal government's ability to process taxpayer refunds, according to The Washington Post.
Union leaders told the newspaper they are expecting the absences to increase as part of a coordinated protest.
Last week, the Trump administration called back about 36,000 federal employees ahead of the tax filing season, bringing the total number of IRS employees working during the shutdown to about 57% of the workforce.
Many of the IRS employees who were called back are using a union contract provision that allows them to be absent from work if they suffer a "hardship" during a federal government shutdown, labor groups told the Post.
"After a month with no pay, real hardship does exist for IRS employees including not having the money needed to get back and forth to work or to pay for the child care necessary to return to work right now," Tony Reardon, president of the National Treasury Employees Union, said in a statement provided to CNN.
"I believe that IRS management understands the stress that employees are under and is doing its best to accommodate the very real hardships employees are experiencing," Reardon said.
He added that the union does not support employees using the exemption as a form of protest, "but we do support people using it for true financial hardship."
"I want to reiterate that even as IRS employees continue to struggle with a lack of pay, they are dedicated to their jobs and returning to work, as directed, if at all possible," he said.
The National Treasury Employees Union could not provide the Post with an official number of absent workers.
The IRS declined to tell the Post how many of its employees are out on hardship leave.
IRS spokesman Matt Leas told the Post that the agency is continuing its work to prepare for the beginning of tax-filing season, which begins on January 28.
"We are continuing our recall operations, and we continue to assess the situation at this time," Leas told the newspaper.
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