. . . Officials say some 800,000 families in the city are poor enough to be eligible.

The Housing Authority currently uses 83,300 Section 8 vouchers annually to help pay the rent for some 270,000 New Yorkers in households with incomes of no more than 50 percent of the median for the metropolitan area, or $35,000 for a family of four. Tenants pay their landlords up to 30 percent of their income in rent; the vouchers cover the rest.

The Housing Authority closed the waiting list for Section 8 vouchers to nonemergency applicants in 1994 because of a drop in federal funding. There are now 127,000 people on the list. Since that time, only emergency applicants, including survivors of domestic violence and families reuniting after foster care, were added.

The 22,000 vouchers became available in part because of a nearly $100 million increase in federal funds for the program nationally, approved in 2006, administration officials said. Another factor, they said, was a 2004 Bloomberg administration decision.

Since the late 1980s, the city had used Section 8 vouchers to help house families moving out of shelters. Faced with federal funding cuts, the city replaced that system in 2004 with another program, Housing Stability Plus, run by the city and the state. City officials say it has helped 10,000 families move out of shelters.

But advocates for the poor and homeless are critical of that program because they say the value of a tenant’s Housing Stability Plus voucher drops by 20 percent a year. Since participants must be on public assistance to be eligible, they say, tenants risk becoming ineligible for the program if they get jobs in order to make up the lost rent.