thanks for the tips All. Manukau Heads is really good for fishing. Quite a long drive from Waiuku.
Without a 4WD and if you don't mind a bit of climbing down a steep sand slope, there is also another way to get to the Waikato River mouth and down to the beach.
Here is a google map with directions
If people concentrated on the really important things in life, there'd be a shortage of fishing poles.