Czech paddlers in January

Prepraing ourselves for our NZ paddling we understood in the last moment, there are two Wairoa rivers - in B.o.P and H.Bay. Are there any other doubles in the NZ?
We would like to meet some locals for paddle tours (sea and white water). Arriving on 30.12. to the North, crossing on 14.1. to the South. We have our foldbar miniraft with.
Vladimir