About 800 homes or businesses in Central Hawke's Bay were without phone or internet for much of Thursday after a mistake by roading contractors near Waipukurau.
Chorus spokesman Nathan Beaumont said contractors doing roadworks about 1.3km from the town had damaged its network on Wednesday.
"There are technicians on site at the moment working to repair the damage but at this stage I don't have an estimated time when the work will be done.
Beaumont said it was "very frustrating" that it had happened through "no fault of our own".
"I apologise to anyone impacted by this issue."