Airport security screeners are calling out of work at an increased rate as the federal government shutdown enters its third week with no end in sight.

The Transportation Security Administration's roughly 52,000 airport screeners are continuing to work through the shutdown because they are considered essential, but their next paycheck might not arrive on time if an agreement to reopen the government isn't reached soon.

That's contributed to an increase of hundreds of TSA officers at several major airports calling out sick, according to a Friday report from CNN.

That includes two to three times as many people calling out at DFW International Airport than usual, an unnamed official with the union representing TSA employees told CNN. CNN reported 25 to 30 people per shift typically called out sick at DFW prior to the shutdown.

Union officials suggested that while some people were calling off to protest the lack of pay, others had to work additional jobs to pay bills or care for their children.

A union leader told CNN as many as 170 TSA employees at New York's JFK International Airport called out each day this week.

The union, the American Federation of Government Employees, did not return a request for comment Friday.

DFW Airport spokesman Casey Norton said waits at security checkpoints in recent weeks have been in line with holiday travel periods in previous years.

TSA spokesman Michael Bilello said the agency is closely monitoring the situation and acknowledged wait times could increase depending on the number of employees who call out sick.

"Call outs began over the holiday period and have increased, but are causing minimal impact given there are 51,739 employees supporting the screening process," he said in a statement.

Bilello said the agency screened 2.2 million passengers Thursday with 99.8 percent waiting less than 30 minutes. He said security standards and effectiveness would not be compromised by the shutdown.

"TSA is grateful to the agents who show up to work, remain focused on the mission and respectful to the traveling public as they continue the important work necessary to secure the nation's transportation systems," Bilello said.

TSA employees have not missed a paycheck yet but are due to be paid Jan. 11, something that won't happen if the government is still shut down. The employees would still be compensated for the hours worked whenever the government reopens.