Mayor Bill de Blasio called congestion pricing an “inconceivable” option for New York City on Monday — even after Gov. Andrew Cuomo recently endorsed the concept.

De Blasio noted historical opposition to congestion pricing among state Senate Republicans and voiced his own outer-borough “equity” concerns at an unrelated news conference in Brooklyn.

The governor’s endorsement “doesn’t fundamentally change my assumptions on its viability,” said de Blasio, on the prospect of state lawmakers passing a congestion pricing bill. “So long as this current Republican state Senate leadership is in place — I think it’s inconceivable, particularly given the focus that the current Republican leadership in the Senate has on Long Island.”

The subway system sits at the heart of the congestion pricing debate in New York City. Cuomo and proponents of congestion pricing believe new city tolls could help pay for long-term subway improvements. The governor only came out supporting the concept earlier in August after the mayor announced his own idea for Albany to fund the MTA: a millionaires’ tax.

“I’ve never been in favor of [congestion pricing],” said de Blasio, who has been at odds with the governor over funding the state-run MTA and other issues. “I’ve never seen an example of it that I thought was fair.”

Former Mayor Michael Bloomberg failed to institute a congestion pricing plan in 2008, gaining little ground in Albany where there was strong bipartisan opposition led by then-Assembly Speaker Sheldon Silver.

A 2015 proposal called Move New York arose from that attempt, with tweaks to Bloomberg’s model to create more equity for the outer boroughs.

The Move New York proposal would add tolls to the city’s East River bridges and would also charge vehicles as they enter or exit midtown Manhattan across 60th Street, while simultaneously reducing the existing tolls on outer-borough bridges that experience far lower traffic volumes.

The plan, which has gained support in Albany, would raise about $1.3 billion in new revenue annually while also reducing traffic, according to Move New York.

It’s still unclear what Cuomo’s congestion pricing proposal will look like. He is expected to include details in his 2018 State of the State address. Jon Weinstein, a spokesman for Cuomo, said the governor is working to build on past proposals and form a plan that will be palatable to the outer boroughs.

“Congestion pricing is an idea whose time has come,” Weinstein said in a statement. “And we would expect that anyone interested in real, achievable solutions to the decades-long problems plaguing the city’s transportation network would join with us.”

With Laura Figueroa