A number of detections were made at the weekend and police say officers will continue to target those who they say are breaking the law on the roads.
PSNI Foyle say: “This weekend your City Centre NPT conducted a joint operation with our colleagues in traffic enforcement targeting illegal taxis and vehicles with illeal modifications.
“A total of 8 vehicles were served with either a prohibition notice or issued penalty points and a fine.
“When you pay for a taxi you have the right to expect it is fully road legal and has all the required documentation.
“Thankfully most of the hard working drivers in the city are compliant.
“But we will continue to target those who think they can flout the law.”