To get to this cache you turn off at Whenuakite between Tairua and Whitianga. Start from the carpark near Hahei (go through Hahei and turn left at the store) at S36 50.029 E175 47.948. The walk down to the beach at the Cove should take about 30-40 minutes. Make sure when you get to the bottom of the steps you go left to investigate the Cove, don't just use your GPS to find the cache without looking. If your children (if you have any) watch What Now, they have broadcast a show from the Cove, they should be keen to have a look.
The actual cache is hidden a bit above beach level near the base of a popular native tree found in this area. It is a 1.25 litre plastic barrel.
Don't forget to check out other places in this area, there are other signposted features, a lot of info often gets overlooked on the lower deck of the carpark lookout as well.
This locations co-ordinates aren't that accurate, there shouldn't be any need to get wet feet.