Hi Cazme,
Totally depends on surface you are riding on as well as your kite size and type. As Velocity has mentioned, a very light wind with a medium sized foil will be ample on the right surface.
A larger inflateable will be OK if you are riding on grass or harder sand. We are trying to get a bit of a crew happening in WA on ATB's so give us a call if you wanna catch up and check out gear, demo and share riding locations etc.
Good winds,