The MTA’s overtime bill rose last year for the first time since the agency’s 2019 commitment to cut back on the extra spending as the authority faced persistent COVID-related crew shortages, according to new public documents.

Overall agency-wide year-end overtime spending grew by 3 percent, from $1.137 billion to $1.164 billion, according to the documents, which attributed the spike to “vacancy and availability coverage, additional maintenance requirements and adverse weather response.”

Higher costs were driven primarily by New York City Transit, the MTA’s buses and subways division, which saw its overtime tab grow 6 percent year-over-year through November, the last month of available data.

MTA Chair Janno Lieber on Monday defended the slight increase as a “strategic and effective use of overtime in the riders’ behalf” as NYCT struggled to maintain service after a wave of retirements plus a pandemic hiring freeze left them short workers.

“We were struggling with a crew shortage brought on by COVID,” Lieber said. “One of the ways that we successfully fought our way back to 94 percent of service, before Omicron hit, was by using overtime.”

Lieber said the use of OT to close coverage gaps was “different than the overtime that is associated with people taking advantage of the system and has led to some criminal justice activity.”

But the rising costs still frustrate the MTA’s 2019 commitment to reduce extra pay spending after The Post exposed allegations of overtime abuse at the authority. Overtime spending peaked at $1.4 billion in 2018, but had dropped in the years since.

That unsupervised collection of OT wages has also resulted in multiple prosecutions — including of the MTA’s 2018 “Overtime King” Thomas Caputo, an LIRR employee who the feds said conspired with co-workers to land jobs on mega-projects where they could get away with sleeping or playing hooky out of view of management.

The MTA, under previous Chairman Pat Foye, hired consultants in 2019 to develop a plan to prevent fraud in the future. The firm urged officials to scrap paper-based accounting for “biometric” fingerprint timeclocks. That effort has met roadblocks, most recently from a hack that limited the MTA’s access to some timekeeping data.

A November report by the MTA inspector general accused the agency of “shifting priorities” away from OT reform — a charge Lieber has vehemently denied.