Democratic mayoral hopeful Bill de Blasio has been mum on critical delays in affordable housing at Atlantic Yards in Brooklyn, because the project is run by a pal who helped fund his campaign, critics charged Monday.

The controversial $4.9 billion project — which includes the completed Barclays Center — is run by Forest City Ratner, whose owner, Bruce Ratner, co-chaired a 50th-birthday fund-raiser for de Blasio in 2011.

Republican mayoral nominee Joe Lhota said de Blasio has been MIA on the housing delays overseen by his pal’s firm.

“Bill de Blasio has been all talk and no action when it comes to affordable housing,” Lhota said outside the arena. “He’s been silent because he’s been bought.”