Chorus said it expected to report a $7 million hit to its annual earnings before interest, tax, depreciation and amortisation (ebitda) due to the impact of Cyclone Gabrielle and flooding across the country.
It had previously said ebitda would be between $675m and $690m in the 12 months ended June 30, before the storm impact.
The earnings update excluded future capital spending to replace the network.
Even with the hit, ebitda of between $668m and $683m in the June year would be an increase on the $660m reported last year, which was at the upper end of guidance.
Chorus added 19,000 fibre connections in the three months ended June 30, taking it to 1.03 million connections.