"This takes apart many of the supports to people who are particularly vulnerable," Schwarz said.
He labeled the proposed budget cuts "a recipe for disaster."
Corbett's budget would cut $41 million for human services. In addition, the budget would eliminate about $65 million in general assistance money that helps disabled and sick adults, domestic violence survivors, adults in alcohol- and drug-treatment programs, and others in similar situations.
Jonathan Stein, general counsel for Community Legal Services, which has many clients who receive general assistance, said the cuts to that funding would affect 35,000 people in Philadelphia. In Pennsylvania, 67,789 people receive a total of $150 million yearly. In most counties, general assistance pays $205 per month.
Corbett's plan also would eliminate an additional $159 million in state-funded medical assistance to general assistance (GA) recipients, Stein said. The cuts would only increase costs, he said, as more poor people turn to churches, homeless shelters, and community assistance agencies, many of which are already under immense financial pressure.
"Fewer than one in 200 Pennsylvanians receive GA, but for those that do, it is a critical safety-net benefit that can be the difference between life and death," Community Legal Services said in a statement.
In recent years, the city has endured multiple rounds of cuts for human services.
Between fiscal 2009 and 2012, the state reduced funding for AIDS prevention 40 percent, for emergency food 13 percent, and for mental-health services 22 percent.
Despite those cuts, the city has been able to increase its inventory of permanent housing with supportive services 55 percent for single adults and 194 percent for families. The number of homeless single adults in shelters and on the street, meanwhile, fell 20 percent from January 2011 to January 2012.
But that progress is threatened, Schwarz said. Most of the budget cuts would affect the city's ability to help poor people with mental illness, intellectual disabilities, or addictions.
Among the specific areas cited by Schwarz:
Half of the 260 individuals with intellectual disabilities who receive employment or vocational services would lose those supports.
Six of the eight walk-in emergency centers for mental-health care would have to close, while one of the two mobile teams of mental-health specialists doing outreach with the homeless would be eliminated.
At residential addiction-treatment centers, 437 spots would be cut.
At homeless shelters, case managers would be reduced.
Michael Covene, deputy commissioner of the city's Office of Behavioral Health and Intellectual Services, said the city currently funds congregate housing for 2,100 poor people with mental illness. That number would be cut by about 400 if the Corbett budget were implemented.
"This is going to force a mind-set change, where we'd have to say no to certain things," Covene said. "The magnitude of this is greater than anything I've ever seen."
Contact staff writer Jennifer Lin at 215-854-5659, firstname.lastname@example.org, or j_linq on Twitter.