An Australian university professor and her sister have been found dead in a shallow grave in the Argentinian city of Mendoza over the weekend.

The close-knit academic community of agricultural scientists in NSW are in shock following the discovery of Lily Pereg, 54, the professor of Microbiology at the University of New England, and her sister, Pyrhia Sarussi, 63.

Lily Pereg (left) and her sister Pyrhia Sarusi have been found dead in Mendoza. Credit:Facebook

Police found the pair at the bottom of a property occupied by Ms Sarussi's son, Gil Pereg, 36. Police prosecutors have arrested Mr Pereg and charged him with murder.

Ms Pereg was appointed a full professor at UNE just days before she travelled to the US and on to Argentina. The pair were last heard from on January 11, local media reported.