The MTA’s $51.5 billion capital plan was approved without oversight from the city Wednesday — after Gov. Andrew Cuomo refused to convene a review panel amid a spat with Mayor Bill de Blasio.

The deadline for the Capital Program Review Board to review the hefty five-year construction budget ended at the stroke of midnight, meaning the MTA can officially begin allocating funding for the plan with no questions asked.

Cuomo refused to convene the four-person panel — consisting of one appointee apiece from Cuomo’s office, de Blasio’s and both chambers of the state Legislature — unless the mayor appeared in person, insisting the decision was too monumental to be given to a proxy.

But de Blasio, who wanted budget aide Sherif Soliman to represent City Hall’s interests, declined, ceding the city’s veto power over the massive infrastructure plan.

The MTA’s board — which is dominated by Cuomo appointees — green-lit the plan in September.

City Council Speaker Corey Johnson — who has demanded transparency as he and other council members weigh sinking some $3 billion of city funds into the plan — railed against the outcome.

“New Yorkers need a strong voice for the city in every single phase of the capital plan process, which to this point has been rushed and lacked transparency,” Johnson told The Post.

“I’d like to see the CPRB meet publicly and answer all the questions I raised at the council hearing we had on this, since I’m still waiting for answers,” he said.

Democratic state Sen. Andrew Gounardes (D-Brooklyn) also called for more accountability.

“What the MTA needs besides more reliable service is transparency and accountability,” he said. “It’s vital that the CPRB meet to review and approve the billions of dollars of necessary transit investment so riders can have faith that the process is working as it’s supposed to.”

Cuomo spokesman Rich Azzopardi shot down critics’ calls for a board meeting, arguing the board is not required to meet and has never met in the past.

“There is no ‘convening:’ Any appointee has the power to veto the plan and the speaker and the majority leader, who nominated themselves, did not. ‎Anyone saying otherwise has no idea what they’re talking about,” he bit back.

MTA Chairman and CEO Patrick Foye nevertheless lauded the panel’s default “approval” of the plan.

“The MTA is pleased the bold 2020-2024 Capital Plan has been deemed approved by the Capital Program Review Board,” he said in a statement.

“The plan is both historic and transformational for the largest transportation system in North America, and we’re ready to get to work to deliver for New Yorkers and improve the commutes of our nearly nine million daily customers. We look forward to continuing to work with our partners at the city and state levels.”