Basically, combat and flip knives are illegal to be held in
possession. They are classified as 'scheduled weapons'. Meaning
they have no other use, except as a weapon.
Whether you carry it on the streets, or you have it at home,
these are illegal and is deemed as your motive to be to use it for
harm.
I'm not sure about rubber trainer knives, but why will you want
them for?
No need to act garang and carry whatever knives for self-defense
crap...you'll be in deep shit even if you really encounter a threat
and you draw up a knife as defense...you'll almost certainly be
charged for possessing a dangerous weapon.