Etrema janjukiensis is an extinct species of sea snail, a marine gastropod mollusc, in the family Pseudomelatomidae. Fossils of the species date to early Miocene strata of the Port Phillip Basin of Victoria, Australia, and the Bass Basin of Tasmania.
In the original description, Powell described the species as follows:
The holotype of the species measures in height and has a diameter of .
The species was first described by A. W. B. Powell in 1944. The holotype was collected at an unknown date prior to 1944 from Fossil Bluff Sandstone at Fossil Bluff, a location close to Wynyard, Tasmania. It is held by the Auckland War Memorial Museum.
This extinct marine species occurs in early Miocene strata of the Port Phillip Basin of Victoria, Australia, and the Bass Basin of Tasmania, including the Puebla Formation and Freestone Cove Sandstone.