Mayor Bill de Blasio on Wednesday vowed to lobby Albany to pass a vacancy tax that would penalize landlords who leave shopfronts empty.

“It feels to me as a New Yorker…it used to be there were some storefronts vacant – and for a limited period of time – and now you have lots of storefronts vacant for years. And that’s a blight on neighborhoods,” the mayor said at an unrelated City Hall press conference.

“It also hurts retailers — especially newer retailers — because those properties being made available at a fair price would help retailers to start up. It’s an artificial attempt to jack up the rents by taking properties off the market.”

Manhattan’s overall vacancy rates doubled from 2.1 to 4.2 percent between 2012 and 2017, according to a City Council report last year.

De Blasio first called for the vacancy tax last year during an appearance on WNYC radio, joining Manhattan Borough President Gale Brewer, whose office has been pushing for the tax since 2017.