The protesters are seeing red — but cops are seeing green.

NYPD officers have collected “several million dollars” in overtime because of the flood of activists clogging city streets to demonstrate against pro-cop grand-jury decisions in New York and Ferguson, Mo., law-enforcement officials told The Post.

“It’s a good time of year to get it,” one law-enforcement source said.

“If [the protesters] want to pay me so I can make sure all my Christmas bills are paid, that’s fine with me,” said another.

Officers on time-and-a-half pay from commands across the city were pulled into Manhattan to follow around the agitators — who Police Commissioner Bill Bratton said are “wandering aimlessly” and just looking for “a night out.”

But while some cops are clocking more than 16 hour days — starting at 7 a.m. and not getting off until almost midnight — most aren’t complaining because of the hefty holiday paychecks.

“A lot of cops are going to make a lot of money this holiday season,” one veteran police official said. “There’s no question about that.”

Some have already worked three overtime shifts equaling 36 hours of extra pay. That adds up to an “overtime bonus” of $1,000 or more.

Additional reporting by Yoav Gonen