ATO Tax
What the budget measure kills are Australian residents who are sent O/S by their employer for a period greater than 90 days but not long enough to claim themselves non-resident under an old agreement where the employer states they are going to benefit from their employees time away, so the ATO agrees to this, the resident goes away with no tax. Generally, at most countries where they end up (UK) tax rules mean they don't pay tax there either so walk away with lots in their pocket.
The ATO is simply stopping this sort of abuse, if you go you'll now pay oz tax with a credit for any foreign tax paid. I had a mate who went to London for 6 mths under said agreement earnt 150K and paid no tax in either country legally!