I'm not sure if it is ok for sensitive skin but I always use a brand called 'Jungle Formula' which comes in a spray or a roll on. I also use a plug in from the same brand in the hotel room overnight.

One thing to note in NZ (not sure if it's the same for Oz) - particularly on the South Island but basically anywhere, they have some evil little creatures called sand flies (I think they are the same as the infamous 'White Feet' that we had to fight off in Alaska). They sell special repellants just for these in all the pharmacies there. A number of my fellow travellers bought some but I stuck with the Jungle formula that I already had with me and was fine. I only got bitten once, on the foot, and that was on the plane coming home! 

Have an amazing time!

All the best

Mandy

I have quite sensitive skin and react to bites (and seem to attract insects wherever I go) I found a brand called Incognito really good.

Not been to Oz/NZ but I've used it in Africa and various othe places. 

Enjoy your trip 

P