Kamal Paul, from Paul’s Stop & Shop in Montagu Street, raised concerns after cars parked in bays by his shop for up to 13 hours at a time.
Shoppers are not allowed to park there for more than 30 minutes, as with the bays directly opposite.
But with the signs no longer there, cars have been parking there for up to 26 times’ that without being fined.
Mr Paul said: “People have been abusing the spaces and parking there to go to work.
“It’s impacting my trade because people can’t park outside my shop and pop in.
“I spoke to a traffic warden and he said he couldn’t ticket anyone because there’s no sign.”
The same sign was also taken down by bays in Dalkeith Place.
Mr Paul contacted Kettering and county councillor Mick Scrimshaw about the issue and the authority has promised to install new signs imminently.
Mr Paul said he had been told the signs were not put up again when streetlights were replaced, but a county council spokesman said this was not true and that they did not know who had taken the signs down.
A spokesman for Northamptonshire County Council said: “We have been made aware that parking restriction signs have been unlawfully removed from a section of Montagu Street and Dalkeith Place.
“New signage will be installed imminently.”