A fibre network outage affected 2300 Chorus customers across Ponsonby and surrounding suburbs on 23 June.
The outage began on Wednesday morning and spread across Grey Lynn, Westmere and Western Springs. Auckland Zoo reported loss of internet service, and some Spark customers also experienced disruption.
Chorus estimated full restoration by 5am on 24 June. A spokesperson said repair crews were working in challenging weather conditions and prioritising vulnerable customers during restoration work.
The company said technicians were investigating the cause from 9am and repairing extensive damage, but did not confirm what caused the outage. "We sincerely apologise for the disruption and thank customers for their patience while we work to resolve the issue," Chorus said.