The majority of the time, the australian slang word "donga" invokes the image of rows of simple transportable buildings laid out on mine sites, designed to be a place for people to sleep and not much else. Occasionally its meaning is expanded to mean any transportable building (also known as demountable, portable, modular, relocatable, or temporary buildings). A mobile home without wheels or a manufactured house can sometimes be called a donga, but generally the more fancy or complex a transportable building gets, the less likely it will be called a donga.
The typical donga is a basic rectangular transportable building, divided into separate rooms by internal wall panels, each room big enough for single person accommodation. Each room has a door to the outside of the building, and a fancy basic donga will have a verandah installed on the front to provide cover just outside the doors. Donga rooms are usually simply furnished with just a bed, a cupboard, and lighting. There'll also be a desk and chair if you're lucky, and maybe a window. There will often be split air-conditioning units installed for each room. There are no water facilities provided, with occupants needing to exit their room and walk across to a separate building for those facilities such as toilets, showers, and basins.
The buildings are relatively cheap to build because of their basic structure and the materials used. The buildings are also designed to be easily transported on the back of a truck. The cheap and functional convenience means that dongas are prevalent on mine sites, however they can sometimes be found as basic accommodation in caravan parks or on farms for seasonal workers.
The word "donga" is pronounced "dong-ah", where "dong" rhymes with song, gong, bong, etc. You will sometimes find it spelt "donger", but it is more commonly spelt "donga". The etymology is a little hard to pin down. There is a news article written in 2016, indicating the naming of transportable buildings as dongas came into use in World War II. The article states it is unclear as to the origin of the word. One possibility is the South African "donga" meaning "a channel or gully formed by the action of water", which may have being adopted as a name for the trenches used to shelter in during the war. Another possibility is "donga" from Papua New Guinea, meaning "house". The article makes note of the different pronounciation of the "g" in "donga" between South Africa and Papua New Guinea.