[Fishcop]

As Peter mentions, Oz has had plastic for quite a while... It's probably a little harder to damage than paper.

As for counterfeiting, well wherever there's a profit motive, you'll have some industrious scumbag having a go... The key thing for the gov and banks is that they can very quickly identify counterfeit notes and protect the currency - it doesn't help you or me at 11pm in bar room lighting, but that was always the case with paper also.