Thank Julia's Fair Work Act.
"In Webster v Mercury Colleges Pty Ltd, Fair Work Australia held that
termination of a sponsored teacher was unfair because of the serious financial
consequences to the teacher and the social dislocation that was inevitable as a
result his summary dismissal."
457 Visa Legal Position
One would suggest that applies to all 457 visa holders who only have 28 days to get another sponsor or leave the country. In several instances 457 visa holders now have greater protection than local employees.