Unrelenting westerly weather since late August have driven Te Anau and Manapōuri Lake levels to their second-highest two-month inflow on record, according to Meridian Energy.

Both Fiordland lakes are used as hydro storage for Meridian's Manapouri Power Station.

Since September 23, the Te Anau lake control gates have been fully open, discharging water at maximum capacity to ease pressure on the system.

Queens Reach on the Upper Waiau River. Graphic. Environment Southland

Flows in the Upper Waiau River peaked at 7.6m (3.6m above normal) on Sunday (25th Oct).

Meridian said that to maintain full generation capacity at the Manapōuri Power Station, they have deferred all non-essential maintenance outages.

Despite these efforts, lake levels are not expected to return to normal until mid-November — even if the rain stops, they said.

A very full Lake Te Anau. Photo: Southland App

Meridian expressed gratitude to PowerNet and electricity distribution businesses (EDBs) across the region, acknowledging their tireless work to restore local networks affected by the weather.

The generation company says it will continue to keep the community informed and hopes conditions begin to settle soon.