The extract below is from "A History of ACT Fire Towers". The full article can be found here.
The ACT Bush Fire Annual Report of 1942-43 noted that a fire tower was erected on Bag Range. When interviewed by Matthew Higgins, a noted historian of the Canberra region, Ted Kennedy – the primary builder of the hut, cited the fear of Japanese aircraft dropping incendiaries to start bushfires, as the reason for building the tower. The tower with its adjacent shelter hut was staffed during the 1940's by Vince Oldfield and Billy Jemmett, alternately, each on 16-day shifts. Extension of Fire Tower System and Bag Range (N.S.W.) Tower.
The fire tower system has been extended by the erection of two additional towers. The first of these is situated on Bag Range at an elevation of approximately 4,100 feet. The site of the tower is approximately 18 miles from Stromlo by air line, but so inaccessible that it takes five hours to reach it on horseback from the nearest point on the Two Sticks road. To overcome this difficulty of access, a lookout man will be required to remain on duty over periods when fire danger is present, and a hut for his accommodation has been provided. A portable radio transceiver set will be made available and a wind generating set has been installed to provide the necessary electric current for the set. Members of the Cavan and Mullion Volunteer Fire Brigade made an invaluable labour contribution by felling trees which needed clearing.
Here is an article about the hut (with 2014 photo) researched and written by David Mitchell in 2019.