For tens of thousands of New York City families, vouchers for free or discounted child care from the city’s Administration for Children’s Services have offered a lifeline as the cost of day care for infants and toddlers has skyrocketed.

Those vouchers could start disappearing in a matter of weeks unless lawmakers in Albany act quickly to fund the program before an impending budget deadline.

The program, which has been significantly expanded to serve more families, already faces a funding gap for the current fiscal year, Jess Dannhauser, the A.C.S. commissioner, said at a City Council hearing last week. The looming shortfall stems from the rollback of Covid-era policies and the rising costs of care.

To continue to offer the more than 60,000 vouchers it currently subsidizes, the agency needs an additional $1 billion in state funding, Mr. Dannhauser said, which the governor and state legislators have not yet agreed to provide. The state’s Constitution requires the budget to be approved in just over a week, by April 1, though negotiations often stretch beyond the deadline.

The ballooning cost of child care has put an impossible strain on working parents of young children in New York City, where the average cost of enrollment in center-based care was $26,000 last year, according to an analysis by the city comptroller, Brad Lander. That figure represented a 43 percent increase since 2019.

Only families earning an average of at least $334,000 annually can afford the cost of child care for a 2-year-old, Mr. Lander’s report found. The median income for a family of three in the New York City region was $139,800 in 2024, according to city data.