A high-tech ID thief — once charged with a massive city ATM scam — has been caught breaking into lockers in a Midtown gym, authorities said.

Hamdija Frljuckic, 43, reportedly had a skimming device, a list of 87 skimmed credit-card account numbers, 11 counterfeit credit cards and six bogus drivers’ licenses when arrested Wednesday while prying open five lockers at the Equinox gym at 420 Lexington Ave.

In 2003, Frljuckic was charged with his brother in a $3.7 million ATM scam.