Saying New York City had failed to follow its own procedure for making rules, a State Supreme Court judge ruled on Tuesday that the Bloomberg administration could not impose a new, much tighter set of regulations on homeless people seeking shelter.

In November, the city’s Department of Homeless Services announced plans for the new rules, which would include investigation of claims by single adults that they had nowhere else to go. In public statements at the time, Seth Diamond, the department’s commissioner, said the new policy would most likely reduce the shelter population by about 10 percent and save the city $4 million a year. In the fall, the shelter population reached a record high of 40,000 people.

The Legal Aid Society, and eventually the City Council, sued, saying the policy was “mean-spirited” and violated a 1981 consent decree that required the city to provide shelter to anyone who sought it. They also argued that because the city tried to impose the rules quickly — in only days — it did not comply with the City Administrative Procedure Act, which requires a process of public vetting. As a result of the litigation, the city did not begin carrying out the rules.

On Tuesday, Justice Judith J. Gische of the Supreme Court ruled that the department had ignored the law by trying to rush the rules onto the books. The rules, which are similar to those that have controlled the admission of families to the shelter system for nearly 15 years, would have forced single shelter applicants to prove, among other things, that they could not stay with a relative.