Transportation Security Administration workers at several major airports around the country, working without pay since the partial government shutdown began Dec. 22, have been calling in sick in heightened numbers, according to union and airport management officials.

More than 150 TSA employees, many of them responsible for screening passengers, called in Friday morning at Kennedy International Airport in New York to say they were ill or otherwise unable to work their shifts, according to a union official with knowledge of the situation.

The staffing gap was covered by other officers, who are also working without pay, the person said.

At Daniel K. Inouye International Airport in Honolulu, many travelers — both locals and visitors — were unaware of the TSA sickouts or call-outs at some mainland airports.

State Department of Transportation spokesman Tim Sakahara said in an email, “HDOT has not experienced significant impacts to travelers as a result of the federal government shutdown as essential safety personnel have continued to report for work.”

A Honolulu TSA agent, who declined to be named, said he was aware of a sickout involving 150 employees at a mainland airport. “Here, I don’t know of anyone calling in sick.”

The so-called call-outs have spiked to three times their normal level at Dallas- Fort Worth International Airport, where an average of 25 TSA employees usually call in sick per shift, a local official of the agency told CNN, which first reported on the story.

The shutdown has left 800,000 federal workers either on furlough or working without pay because their jobs are deemed essential.

Dissatisfaction and anger have been growing over the past few days as workers face their first period without a paycheck this weekend. Increased sick calls at TSA could increase the pressure on the White House and Congress to resolve the shutdown more quickly.

A federal official, who spoke on condition of anonymity because the official was not allowed to comment publicly on the matter, said the call-outs seemed to be a coordinated protest. But union officials said many of the workers who called in sick were most likely seeking alternative temporary employment to make up for lost wages.

TSA spokesman Michael Bilello told the Honolulu Star-Advertiser on Friday, “There is no sickout anywhere. This is not a real story.”

However, he said in an email, “TSA is closely monitoring the situation. 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.”

“Security effectiveness will not be compromised and performance standards will not change,” he wrote. “Wait times may be affected depending on the number of call outs.

“To date, however, screening wait times remain well within TSA standards. Yesterday, TSA screened over 2.2 million passengers. Overall, 99.8% waited less than 30 minutes.”

At Honolulu’s airport the TSA checkpoint lines were short mid- to late Friday afternoon, possibly due to few departing flights.

Two checkpoints in Terminal 2 were closed, and travelers had to walk to an open checkpoint at the far end of the terminal.

Greg Brown, 61, of Birmingham, Ala., said his plane was delayed an hour on the tarmac in Atlanta before taking off for Hawaii, but not because of TSA.

“Because of the government shutdown, there were no air traffic controllers,” he said. “They got the problem solved, but we sat in the plane for about an hour.”

Hanna Rifaey, 38, of Washington, D.C., said, “We feel very bad for TSA having to work on the holidays” and not being paid.

She and her family flew out Dec. 21, before the government shutdown.

Her husband, a lawyer for the Department of Commerce in Washington, is not an essential employee, so he may not be going back to work for a while.

Rifaey said they didn’t look forward to returning home and wanted to stay in Hawaii. “D.C. is always very depressing during a shutdown,” she said.

“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 in an email.

Sakahara urged travelers to give themselves plenty of time to pass through the security checkpoints.

He also encouraged travelers to “pack extra patience and show aloha,” as essential federal employees do not know when their next paycheck will arrive.

Bilello said exempt TSA employees have not missed a paycheck. Their next paycheck, which they might receive if funds are appropriated by midweek, is due Friday.

The New York Times and Star-Advertiser reporter Leila Fujimori contributed to this report.