The city’s 150-plus labor unions, all working under expired contracts, must make concessions on health care to get bigger raises, Mayor Bill de Blasio’s budget chief said during a City Council hearing Wednesday on the mayor’s preliminary spending plan.

“We’re going to treat the workforce with a respect that they’ve not been treated with, and at the same time, protect the taxpayers and do something that’s affordable,” budget director Dean Fuleihan said. “There has to be offsetting savings, and ... [de Blasio has] specifically mentioned and has repeatedly mentioned health savings.”

Labor negotiations are the city’s biggest fiscal hurdle this year, with about 300,000 municipal workers clamoring for raises, benefits and about $7 billion in retroactive pay requests. The nonpartisan Independent Budget Office, analyzing several scenarios, estimated raises of 2% going forward on top of retroactive raises of 4%  could cost the city $7.1 billion in 2014.