Bayman, does the unpaid amount relate to a fine from a council, or is it a claim from a private company?
If it is the latter then do not, under any circumstances, indicate to them that you may have been the driver (even if you were). Although it's highly unlikely that you could even remember anyway...
Private company "parking fines" are simply claims for liquidated damages for an alledged breach of contract between the vehicles driver and the provider. They claim that the terms of that contract are adequately displayed at the entrance of the facility, and that by entering the premises the driver has agreed to those terms.
The fatal flaw is that they obtain the details of the registered owner, and issue the claim to them. Simply deny that you were driving, and refuse to identify who may have been. They can not demand that you make a stat dec in respect to this, so DO NOT make one (especially if it is a lie!).
Their ploy is to make a reduced claim, hoping you might accept the lesser amount, and threaten legal action if you do not. Do not pay it. If they keep harrassing you, send a letter referencing ASIC's debt collection guidelines and threaten to raise the matter with ACC and ASIC.
If you have previously admitted "liability", then your course of action is different... argue that their claim is a grossly inflated figure compared to the "suffering" your "breach" may have caused them, and ask them to justify the amount. You can reference the Trade Practices Act and threaten ACCC again.
This is not advice, but has recently proven successful for me.
These resources might be of use...
http://www.trafficlaw.com.au/forum/view ... ad8dc4529fhttp://www.aussielegal.com.au/forum/for ... D~2444.htmHowever, if it is from a local council authority, then it may be a legally enforceable fine (although the length of time of the claim being presented may offer some defence), and you will either have to prove that you were not the driver, or at worst prepare a stat dec claiming that to be a fact (but do not lie in a stat dec, unless you are keen on some jail time!)
Good luck!