It is LEGAL in Australia and New Zealand. The legislation passed several years ago was in the spirit of having those who use CC to bear the merchant fees. And it actually works.

In fact many restaurants would put up a sign if paying by cash, you get a 3% discount.

What practiced in US and Canada, having non CC customers to bear the merchant fee in the form of higher price because they do not get cash discount, does not mean other parts of the world would be the same. Here in US many gas stations have lower price for paying cash, just sayin.