My boys feet are very much like this, though he has inherited my flat feet so we have been fitted with orthotics about 5 months ago now and he is almost 2.
They say that all kids are flat until their muscles develop but if the ankle is rolling in it may be a problem.
If your in Sydney you don't need a referal to podiatrists or Physio... If your near the hills area in sydney i know and I will recommend a great kids Physio and our podiatrist too.

Good luck, feet are expensive but take it from me, I was never treated when I was young and have always had hip and back issues which steam from the feet.