The serial burglar accused of breaking into Robert De Niro’s Manhattan townhouse was allegedly free to strike again thanks in part to a loophole in New York law that let her blow off a monitoring ankle bracelet, The Post has learned.

Shanice Aviles — who was charged with trying to steal De Niro’s Christmas gifts late last year — was meant to report to the New York City Sheriff’s Office for electronic monitoring after she was busted again in June for allegedly ripping off a TJ Maxx store in Chelsea.

But Aviles, 30, never made an appointment, allowing her to fall back under the radar and allegedly commit another break-in at Columbia University the following month.

That’s because the process for defendants to be placed under electronic monitoring is based on the honor system, legal experts said.

“It’s obviously absurd that someone is released pursuant to the understanding they will get fitted for an ankle bracelet and nobody shows up and nobody knows,” former Manhattan prosecutor Mark Bederow said Thursday about the botched attempt to keep tabs on the career criminal.

“The expectation becomes, ‘Well, we will find out when that person gets arrested,’” Bederow noted. “That’s ridiculous.”

Aviles was released from Rikers Island on $40,000 bail in May, six months after the break-in at De Niro’s rented Upper East Side townhouse — only to wind up back in cuffs June 5 for allegedly snatching $416 worth of merchandise from the TJ Maxx on Sixth Avenue near West 19th Street.

The judge in the De Niro case, Laura Ward, hauled Aviles back in court following her new arrest, giving