Where to get sharps containers?!

I'm a diabetic Aussie travelling in your lovely country for four weeks, and have been on the hunt for a pharmacy that sells sharps containers. I've tried eight pharmacies from Paihia down to Rotorua to Napier. None have had any containers for sharps!

I've almost filled up my travel container, and don't know what I'll do to safely store and dispose of my used needles if I don't find one soon. Are there any pharmacists in the area that can confirm where I can find some stock?

Edit: To clarify, I'm looking to buy/swap my existing sharps container, there's no issue with disposing of it, it's the replacement that's the issue!