There is no shortage of turbine qualified pilots in Australia who could easily meet the experience criteria for any regional airline here - or most places for that matter.
But it would appear that either the locals don't want to work for the conditions on offer or:
(CONSPIRACY THEORY HERE) certain companies would rather 'own' their staff by having them shackled to a 457 Visa, which is employer-specific.
They haven't yet got to grips with the idea that the hassle of importing a pilot, getting him/her up to speed on the local scene, through the CASA malarkey etc does not save money when the same pilot moves on after the shine of living in exciting Australia wears off.
But it's great way to spend a couple of years seeing the country and being (sort of) paid for it Just check the bond arrangements first!.