Dyfed Powys Police are warning motorists in Narberth that they are putting people's lives at risk.
The fire station in High Street is experiencing problems getting its vehicles out due to people's cars.
The left-hand side of the High Street is single yellow lined and has no parking between 8 am and 6 pm.
Inspector Andy Phillips, of Pembrokeshire Roads Policing Unit, said: "People are also parking inconsiderately on the right-hand side of the road.
"For example, they are leaving either their bonnet or rear end of the car sticking out in the road as they have tried to park in a space which is too small for them.
"The neighbourhood policing team have issued over 300 warning notices to motorists, but that seems to have had no effect.
"We will now be out issuing fixed penalty notices as this behaviour really is putting lives at risk."