The water level in the country's biggest lake — Lake Taupō — is dangerously low for this time of the year.
It is more than 30 per cent lower than what it should be.
Following two dry years and not much snow, the lake is just six centrimetres away from its lowest recorded level.
This has left charter business owner Simon Jolly unable to remove his big boats from the water for maintenance, which normally happens during winter.
Harbour master Heath Cairns said only five of the lake's 18 boat ramps were operational as a result.
"There are implications, especially for the bigger boats. The commercial operators here in the marina — some of them are touching the bottom within their berth."
Taupō Mayor David Trewavas said "we're very, very worried", as the lake was 15 centrimetres away from its lowest operation margin, which could affect everyone downstream.
Lake Taupō feeds the Waikato River, which provides drinking water for Auckland and the Waikato.
It also helps cool the Huntly Power Station, but Mercury Energy said this won't hit consumers in the pocket.