Authorities on Nauru arrested the most senior Australian health professional treating people at the immigration processing centre and ordered her deported back to Oz.

Dr. Nicole Montana works for Australia's health contractor IHMS, which said she was stood down for an unspecified "breach of Regional Processing Centre rules".

"A replacement Senior Medical Officer is already in Nauru, there has been no impact on the services provided to transferees," read  the statement.

It's not clear who gave the order to arrest her or why. Contacted by The Guardian newspaper, the Australian Department of Home Affairs declined to comment and referred questions to Nauru and IHMS.

This is the latest flare-up in deteriorating relations between Australia and Nauru.  Last month, the island deported Dr. Montana's predecessor Dr. Christopher Jones in a dispute over the medical treatment of refugees.  Also in recent weeks, the Nauru government ordered accused the famous charity Medicins Sans Frontieres (MSF) of being "political activists", cancelled its contract to provide mental health services to both refugees and residents, and ordered workers off the island.