The gauge had two small radioactive sources and although the amount of radioactive material was relatively small and was encapsulated in stainless steel, if it was removed by unskilled operators, it would pose a potential public health and safety concern.
"No one should attempt to operate or disassemble the gauge, due to the adverse health effects if they do," Mr Paynter said.
"We would like to recover the gauge, fully assembled and to ensure there is no risk to the public; I appeal to the person who took the vehicle to do the right thing and let us know exactly where the gauge is so that we can have it collected."
Any one with any information was urged to contact their nearest police station or the police communication centre.