An MTA coding error rendered some 9,200 monthly Metro-Cards useless Monday morning, causing widespread confusion among thousands of Long Island Rail Road commuters affected by the mistake.

Some 7,100 LIRR Mail & Ride customers, and another 2,100 on Metro-North, swiped the 30-day, unlimited ride Metro-Cards on the back of their December monthly railroad passes only to get a message telling them they had insufficient fares. Metropolitan Transportation Authority spokesman Aaron Donovan said the Metro-Cards "were not coded correctly" before being mailed out to customers.

"We recognize that this is an inconvenience for our customers," Donovan said. "We apologize for the inconvenience and for the error."

Donovan said the MTA will rectify the problem by crediting Mail & Ride customers' accounts by $118 -- $5 more than the cost of a new monthly Metro-Card, in recognition that some commuters may have paid out of pocket for their subway or bus ride this morning.

Donovan said that, for the remainder of Monday, impacted customers should flash their monthly railroad pass to subway agents or bus operators to gain entry. But they will have to buy a new 30 -- day unlimited ride MetroCard, priced at $112, to use for the rest of the month.

LIRR Commuter Council Chairman Mchairmanein, who was among the Mail & Ride customers affected by the error Monday morning, said that while he understood that "mistakes happen," the MTA should have better communicated with its customers throughout the morning rush.

The LIRR did not publicly acknowledge the situation until after 10 a.m., when it sent out an email to customers and Tweeted abtweeted "processing error."

"The silence from the railroad all morning through this process; That's what gets people upset. They feel like they're out on there on their own," Epstein said. "It's almost like indifference from the MTA. That's the frustrating part."

John Leviness, 52, of Massapequa Park, said he got off his LIRR train Monday morning at Massapequa to find "confusion" at the station's subway entrance.

"There was a huge line of people and I hear all these complaints," Leviness said. "Everybody was like, 'What is wrong?'"

Leviness said commuters eventually began entering through the emergency exit door. It wasn't until he called LIRR's customer service line later in the morning that he was told he should buy another Metro-Card.

"I guess that's what I'm going to have to do," Leviness said. "What happens if you don't have a credit card or you don't have the funds? That's another [$112] out of your pocket."

-With John Valenti