Abstract: A radio activated danger warning system in the form of a radio activated bush fire warning system 10 comprising transmitting means 12 for transmitting a coded signal to a plurality of geographical zones 14, each zone 14 having a unique code assigned to it. The radio activated bush fire warning system 10 further comprises a plurality of receiving means 22 in the geographical zones 14 for receiving the coded signal and generating an alarm to warn of the approach of a fire. Each of the receiving means 22 advantageously includes a GPS receiver and a comparing means whereby, in use, it can obtain its current GPS coordinates and compare them with the GPS coordinates of the danger zone. In use, only those receiving means 22 located in the danger zone and receiving coded signals with the unique code assigned to that zone will generate an alarm.