Electricity generator Mighty River Power has rejected a request to top up the Waikato River for this weekend's Turangawaewae Regatta, citing the impact of the drought in reducing lake levels.
A spokesperson for King Tuheitia says the state-owned enterprise has been extremely helpful in the past, but the hot, dry conditions mean it is not possible to boost the river level.
In previous years, dams have been opened to make the river wider to allow a parade of waka taua or war canoes to paddle three abreast.
On Saturday, the waka will instead travel nose to tail.
Members of Turangawaewae say they have not seen water levels in the Waikato River so low in 50 years or so.