Can I claim tax on international travel insurance?

Why would you be claiming the insurance, what was the purpose of the travel?

I came to NZ on a 1yr working holiday visa. To cover myself travelling I needed to take out International Travel Insurance as the medical aid scheme / company I was on only cover for up to 3 months travel time.

You can only claim the expense if you earned income directly related to that travel and the travel was for a purpose. In NZ, did you work and earn income and pay tax on that income. You cannot claim expenses against foreign employment income if you were gone longer than 183 days as you do not pay tax in SA on that income so there is nothing to claim against.