A passenger tried to board a plane with a gun and ammunition at Orlando International Airport on Tuesday morning, causing a long backup at checkpoints during the post-Christmas travel rush.

The passenger had a carry-on bag containing a Ruger with a separate magazine loaded with 10 rounds of .22-calibre ammunition, said Transportation Security Administration spokeswoman Sari Koshetz.

The passenger, who was not identified, possesses a valid Florida concealed weapons license, but will be charged with carrying a concealed firearm in a place prohibited by law, said Orlando police spokeswoman Michelle Guido.

It was the 91st weapon intercepted by TSA officers at Orlando's airport this year, Koshetz said, adding that it marks a "disturbing and dangerous pattern" across Florida and the rest of the nation.

"Most of the guns our officers intercept are loaded," Koshetz said. "You see the way many passengers fling their carry-on bags onto the X-ray belts in the checkpoints. An accidental discharge could have tragic results."

Koshetz said passengers who bring a gun to a security checkpoint face civil penalties from TSA of up to $13,000, even if they aren't arrested.

The agency has seen a rise in the number of guns brought to checkpoints across the state over the past five years, according to a recent TSA report. So far this year, 505 weapons have been found at checkpoints at the state's largest airports. The largest numbers have come from five of the state's largest airports: Tampa International, Orlando International, Fort Lauderdale-Hollywood International, Miami International and Jacksonville International. Tampa International tops the list with 97 guns, followed by Orlando at 91. Agents intercepted 72 guns at Fort Lauderdale's airport, 52 at Miami's airport and 39 at Jacksonville's airport.

In 2016, 3,391 firearms were discovered in carry-on luggage at 238 of the nation's airports in 2016, an increase of 28 per cent over 2015, the report shows. Hartsfield-Jackson Atlanta International Airport topped the list with 198 incidents, followed by Dallas Fort Worth International Airport at 128. The Tampa and Orlando airports had 79 and 86, respectively, putting them on the TSA's top 10 list for firearms discoveries at checkpoints.

The total numbers haven't been tallied for 2017.

In addition to firearms, TSA agents also intercept thousands of knives, brass knuckles and other hazardous materials at the checkpoints.

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This story has been edited to correct that the gun was not loaded and to correct the spelling of TSA spokeswoman Sari Koshetz's name.