Urgent Antarctica mission to rescue Australian researcher -

Australia has launched an urgent operation to rescue a researcher with a "developing medical condition" from the remote Casey outpost in Antarctica.

The icebreaker RSV Nuyina left from Tasmania last week, the Australian Antarctic Program (AAP) said.

It is travelling thousands of miles to reach the station after an air rescue was ruled out due to harsh conditions.

The AAP said the researcher, an Australian, needs specialist treatment but did not name the condition.