I have no doubt that any management would see contractors as a method of making productivity gains, and the union is very correct in ensuring that any new contract doesn't undermine conditions.
Use the same tactics. Use new contracts as a way of improving remuneration (permanent remuneration). Especially if the contracting process turns into a farce (which it will if they dont offer the right money). Just think about whether denying contractors more money works for you, or against you.....
* I am not a potential candidate at the current offer, and nor is anyone else that I am in contact with.
Gu'luck.