In an effort to reduce the growing number of inmates with mental health and substance abuse problems in New York City’s jails, the administration of Mayor Bill de Blasio announced plans on Monday to significantly expand public health services at almost every step of the criminal justice process.

City officials, who are allocating $130 million over four years to the project, said their goal was to break the revolving door of arrest, incarceration and release that has trapped many troubled individuals in the system for relatively minor, quality-of-life offenses.

The new plan will shift emphasis from punishment for minor crimes to treatment.

The changes include tripling the size of both pretrial diversion programs and the amount of resources devoted to easing the transition from jail back into society. This would represent a significantly different approach to criminal justice in the city, experts said. But they cautioned that nothing of such scale had been tried by a municipality before, and that putting the plan into effect would be difficult.

“I think this is what criminal justice looks like in the 21st century,” said Elizabeth Glazer, the mayor’s criminal justice coordinator, who was a co-chairwoman of a task force of city officials and community leaders that released a report on Monday detailing the changes. “Preventing crime is about more than the police and more than about prosecutors and defense lawyers and courts.”