Thanks for the comment hitspacebar-choice.
The Code allows some products to be unit priced per kg, some per 100g and some per 10g. However, it also requires that all packs of the same product to be unit priced using the same unit of measure. So not any retailer not doing this is not complying with the ACCC administered Code.
However, with some products it can be difficult to comply with, for example if the packs of some items of a product are marked with the weight and others just the number in the pack - for example biscuits and cakes.
I agree that retailers prefer the unit of measure to be small so that the unit price looks low. That is why the standard units of measure in the Code for weight and volume are 100g and 100mL not kg and litre.
The Code also requires unit prices to be accurate.
I encourage you to contact the ACCC (ph 1300 302 502) if you find retailers not complying with the Code.