Two ninja-like robbers, dressed head-to-toe in black, pulled off a brazen, midday heist in a Diamond District store yesterday, tying up the owner and his son and swiping $60,000 in cash and bling before fleeing, police said.

The crooks sprinted out of the West 47th Street shop Namatbefore cops were called at about 2 p.m. — after the victims had wriggled out of their bindings in the shop.

Although the robbers disabled the store’s camera, “there are lots of video cameras on the street,” said one cop at the scene.

Merchants and shoppers were astounded at the brazen daylight heist.

“It takes something like this to make you want to get up and do something,” said one businessmanwho claimed he’d been thinking about a security upgrade.