Gov. Andrew M. Cuomo Tuesday shot down a part of Mayor Bill de Blasio's push for hundreds of thousands of units of more affordable housing.

Just hours after de Blasio mentioned in his State of the City address a proposal to build 11,250 units above the sprawling Sunnyside rail yard, Cuomo spokeswoman Melissa DeRosa dismissed the site as "not available."

"The MTA uses Sunnyside Yards as an important facility for our transportation system, and it is not available for any other use in the near term," she said in a written statement, referring to the Metropolitan Transportation Authority, which Cuomo controls.

The address' focus on more affordable housing -- a $41 billion initiative to build or preserve 200,000 units of below-market-rate units over a decade -- suggests that de Blasio would make it a major focus of his second year in office.

"While the state of our city is strong," de Blasio said, "if we fail to be a city for everyone, we risk losing what makes New York New York. We risk the very soul of this place."

De Blasio said that while gentrification has some benefits, it risks pushing longtime residents out of their neighborhoods.

Other areas targeted by de Blasio for denser development include East New York in Brooklyn; Long Island City and Flushing West in Queens; downtown Staten Island and the Jerome Avenue Corridor in the Bronx.

Amtrak, which owns about 113 of the roughly 200-acre Sunnyside site, is enthusiastic about the plan, the de Blasio administration says. Amtrak spokeswoman Christina Leeds said the railway supports the mayor's "strong interest in advancing affordable housing."

The MTA owns 66 acres; the city owns air rights to 44 of those acres. The city can build above the tracks provided there isn't interference with train operations, the administration says.

Deputy Mayor Alicia Glen said the city would be commissioning a study soon to assess the viability of the plan.

In response to Cuomo's statement, de Blasio spokesman Wiley Norvell said: "Our feasibility study will constitute an exhaustive process undertaken with local stakeholders to activate the Sunnyside Yards while continuing their role as a vital link in the region's rail system. We have engaged the MTA and Amtrak to ensure that any development prioritizes their transit operations."

The costs have yet to be determined.

De Blasio's nearly 90-minute address, in an auditorium at Baruch College in Manhattan, featured a diverse cast: a woman police officer sang the national anthem, a Hispanic pastor gave the invocation and a black woman introduced the mayor.

De Blasio also introduced a plan to bring ferry services to transit-starved corridors of each of the five boroughs. He also wants Albany to greenlight a minimum-wage hike in the city to $13 an hour in 2016 -- and to tie the wage to a barometer so the wage would rise as costs of living rise.

Cuomo's office, which has called for a minimum-wage hike to $11.50 by 2016 in the city, said the state Legislature views the idea as a "nonstarter." It is currently $8.75. As with much of municipal governance, Albany must approve changes to the minimum wage.

Later in the afternoon, de Blasio's press office sent out a long list of positive reactions to his speech from activists, business leaders and public officials. Cuomo's statement was not included.