This bombing-sniffing dog might need a new nose.

A pooch prompted a bomb scare in the Big Apple Saturday after it sniffed out what it believed was an explosive device hidden inside a car — which actually turned out to be rat poop, police sources said.

A K-9 stationed at a private security checkpoint in Lower Manhattan alerted its handlers to a possible bomb in an Acura sedan around 12:30 p.m. as the vehicle approached the checkpoint located at Broad and Beaver streets, near the New York Stock Exchange.

The guards then quickly barricaded the vehicle and notified the NYPD, which responded with an Emergency Services Unit bomb squad.

However, authorities soon realized the presumptuous pooch was actually triggered by rat droppings on an engine block.

The vehicle was allowed to pass the checkpoint after the stinky mix-up, sources said.