Democratic mayoral candidates Christine Quinn and Bill de Blasio vowed yesterday to scrap a $16.5 million annual property-tax break for Madison Square Garden.

“We’re giving a tax break to a company that doesn’t need it,’’ Council Speaker Quinn said outside the Garden.

De Blasio, the city’s public advocate, chimed in, “Amen.”

MSG defended the tax break, which has been in place since 1982, saying other local sports teams also receive subsidies.