i live in the US and have always wanted to go to Australia and England and wanted to know the laws on knives. I would figure in australia knives would be ok. In the US its only legal to carry a knife thats is no bigger than the palm of your hand, though i dont carry an assited opener on me in public unless at work.
I too live in the US and carry three knives and two flashlights 24/7. As far as size goes, there really is no limit until you start to incite a disturbance. When flying to Russia in '93 the security dude at Chicago o'hare airport let me right on with my big Buck knife, so I asked him, "how big a knife would you let me by with?" and he replied that as long as it wasn't some "Jim Bowie" knife it's OK.
There is a big difference in open carry and concealed carry.
I am packing now for my third recent trip to Australia. I carried my full size Swiss Army knife and often a pocket clip knife everyday there, (Victoria) but all the guys in my wife's (Australian) family said to watch out. It a no-no. This trip I will be walking into the local police station and getting their opinion. ANY item can be considered as a weapon, but it must actually be USED as one to rise into the category of "dangerous weapon"
I Australia you can pretty much do as you please in contravention of any legislation if you have "lawful excuse".
It is a thing that you can have, or get, and it is not like a permit. Google "lawful excuse" and look for it on YouTube. You might be surprised what you find.
Lawful excuse is synonymous with a claim of right. (as it is referred to in New Zealand)
So, go forth and discover you real rights and how to secure them.
Don't ever refer to your knife as a weapon, but as a tool you use for chores everyday. Your life IS your work. When you are in a car, about the only place that is not considered "concealed" is locked in the glove box, OR on the dash board. I've had many cops tell me this. Also, a sheath or holster need only hold your piece, but it doesn't have to look like a sheath, OR let someone looking at it know what is inside. It is still not concealed. It is in its sheath in plain view on the dash. This came from a joggers gun holster that just looked like a square pouch worn on the back with (or without) a water bottle. The same applies to a knife.