I see what your saying regarding immigration, however backing up what compressor stall is saying, they have sponsored a number of people in the past in other areas of the organisation.
Yes many pilots in Australia, and doctors and nurses, but to get the right combination of skills and experience is difficult. Its not an entry level job.
The number of people who would have all the qualifications and experience to walk into the job are few and far between, I would not want someone with a bare CPL/MECIR taking me out of a flare lit unpaved bush strip in the middle of the night to a foggy arrival at a larger city airport.
As compressor stall suggested, they could also show that remote bases do have a high turnover, and contracting a person to that base maybe one solution, thats what QLD health does to its overseas doctors to get coverage.