Jones and her children

NEWARK, New Jersey (CNN) -- Hundreds of families are leaving New Jersey's state-subsidized homeless shelters, because of a new law that limits their stays.

New Jersey used to allow homeless families to stay at emergency shelters indefinitely. But under a law that became effective July 1, the homeless can't stay in emergency shelters for more than 12 months -- in their lifetime.

Although some exemptions are made in extraordinary circumstances, the number of shelter residents has been reduced from thousands to hundreds.

State officials explained that the emergency assistance was designed only as a temporary measure to help people get back on their feet.

"It is not, in fact, a housing program ... 12 months has been considered a sufficient amount of time to try to do that," said David Heins of the New Jersey Division of Family Development.

The law has forced many families to make due for the first time without the safety net of emergency housing.

Lelitia Jones, a single mother of three, left the Apostle's House Shelter in Newark for a small apartment nearby. She got a part-time job, but despite food stamps and other assistance, only expects to have $25 a week for spending money.

"I've been mainly thinking about if things don't work out, then me and my children will be out on the street, and I will have to put them up for adoption ... and that is one thing I don't want to do," Jones said.

Social workers and critics of the new law are also worried.

"She's going to be struggling, I know she is," said Sandy Accomando, executive director of the Apostle's House Shelter.

"To say that you can limit emergency assistance is an oxymoron as far as I'm concerned, because by its very nature, emergency is something you can't plan for ... how can you put a time limit on it?" she asked.

CNN Correspondent Gary Tuchman contributed to this report.