Hi Tim,
Not clear from your post what's happening, there's a couple of scenarios.
If you're currently sponsored by a labour hire company with 457 sponsorship rights then you can move actual employers with impunity, as long as you stay with that labour hire company. There's no cost buttociated with this kind of move.
If you move from a sponsoring direct employer to a labour hire company with 457 sponsorship rights then they're probably offering you an inducement of no application fees, and a tax break (the LAFHA) up front and then taking a cut, possibly as much as 10%, of your salary.
If you're moving from one direct employer to another direct employer which is going to park you as a contractor in some outsourced operation then it can't work - the 457 scheme is only for employees, not contractors.
If you move from one direct employer to another direct employer then the total visa application costs of A$500 need to be paid to DIMIA and the employer would probably need an agent to figure out the fine print. According to the MARA, the average cost of that is about A$2902 but it works out less than the 10%, particularly over the four years of a visa.
Tracy - in your situation you'd be most likely to be in this last scenario.
Cheers,
George Lombard
www.austimmigration.com.au
-- www.austimmigration.com.au