The NYPD’s aggressive lock-’em-up policy for teen lawbreakers is swamping already overloaded juvenile jails–and is costing taxpayers $1.6 million in extra overtime pay.

The population explosion has prompted the Giuliani administration to propose converting an adult prison barge for teen use. The city recently built two new juvenile detention facilities, but they are too small to handle the torrent of incoming arrests. Now officials are warning that the system may collapse without an infusion of new non-uniformed workers.

“I have never seen a more drastic situation,” the juvenile center employees union president, Ernest Browne, told city council youth committee members last Wednesday. “How do you think you would operate if you worked 16 hours a day, five days straight? You can’t function. You’re not as alert as you should be in a job where being two seconds late could mean a major incident.” To ease the strain, he urged the hiring of 70 new youth counselors.

The average population in the city’s two youth lock-ups was 315 during the past six months, a 25 percent increase over last year. And there are no signs of leveling off–as of last Friday, the population was 367. Newly appointed Division of Juvenile Justice (DJJ) Commissioner Tino Hernandez conceded that the department needed more help and told the council he had recently hired 43 new counselors. Under pressure from Browne and councilmembers at the hearing, DJJ spokeswoman Sarina Roffe reported that an additional 23 counselors will be hired.

Even with the hires, DJJ has still slated an additional $3.6 million for overtime costs this year. “It’s not possible to estimate overtime,” Roffe added. “There is a high staff turnover and the inmate population is unpredictable.”