Dr Lily Pereg, an associate professor of microbiology at the University of New England, and her sister, Pyrhia Sarussi, 63, had been in the country visiting Ms Sarussi’s son, Gil Pereg, 36.

The pair were last heard from in the early hours of January 11, local media have reported.

Argentine newspaper, Perfil, reported the two sisters were on holiday in Mendoza, a city of about 120,000 people in the centre of the Argentine wine region, and had rented an apartment.

Gil Pereg is the local chairman of five companies established by his mother, Pyrhia, who lives in  Israel. Dr Pereg was also brought up in Israel where she obtained her undergraduate degree.

She moved to Australia in the mid 90s and was attached to the Department of Agricultural Science at Sydney University where she completed a PhD.

Later, Dr Pereg moved to the University of New England and was recently made a full professor.

According to local media reports, Gil Pereg has told police in Mendoza that he saw the two sisters board a bus to return to their rented apartment in the early hours of Friday morning.

“Later it was also learned that Pereg’s economic situation was complicated and during a police raid on his home striking elements were found for investigators,” according to the Perfil report.

Vered Sarussi, the daughter of Pyrhia Sarusi, said in a Facebook post that the women’s last known whereabouts were at their rented apartment in Mendoza and asked that anybody with any knowledge of the two to contact lostinmendoza2019@gmail.com

smh.com.au