The three main ones would be the Waikato, the Clutha (Mata au), and the Waitaki. There is a very large hydro station operating directly from Lake Manapouri into Doubtful Sound, with no river at the dam. in addition, there are many smaller, but locally significant, hydro plants on other rivers.
There are three: Aratiatia, Atiamuri, and Arapuni. All are hydrolectric dams.
The largest hydro power scheme in NZ is that between lake Manapouri and Deep Cove in Doubtful Sound. It is permitted for 730MW, but could generate 830MW if needed.[Benmore Power scheme on the Waitaki River is the next largest with a capacity of 540MW, but current work should increase that to 610MW.]
From what i have been told they are 2 separate rivers but the Rainbow river flows into the Wairau river at the headwaters.
The Clutha river.
Clutha (matau) River.
on the Waikato river in NZ
mataura
The Waikato in the north island, is NZ's longest river , and in the south island, the Clutha (Mata Au) is NZ's river with the greatest flow.
It is 17 miles from Eastbourne to Wellington Railway Station.
the furthest river north is kawarau
The Clutha
TV 2, that's for NZ