Some of the "German" tanks are actually mocked-up Sentinel tanks from a canceled Australian cruiser tank project; their appearance represents the only time Sentinels were ever used outside of testing.
According to the National Film and Sound Archive of Australia, the film utilized "documentary footage from front-line cameramen."
Interiors such as dugouts and underground firing posts were built at the Commonwealth Film Laboratories in Sydney, New South Wales.
The name "The Rats of Tobruk" refers to the troops, mostly Australian, who held out against German Gen. Erwin Rommel's legendary Afrika Korps at the Libyan port of Tobruk during 1941. This so-called Siege of Tobruk began on 4/10/41 and ended in November of that year. "The Rats of Tobruk" held out for an incredible 250 days before being relieved by British forces.
When the film opened in theaters in Australia, simultaneous premieres were held in Melbourne and Sydney.