The spokeswoman said it was not immediately clear what caused the Napier cut, which occurred between Napier and Waipukurau.
The outage affected Napier, Hastings, Whakatane, Gisborne, Tauranga and Wairarapa.
Vodafone NZ wholesale and infrastructure director Tony Baird urged contractors to take extra precautions before digging.
"With alert level 3 construction work back under way, and with shovel-ready projects likely to get started, we urge contractors to check before they dig at all times," he said.
"Mobile and internet broadband services rely on underground fibre cabling to function. While we appreciate that contractors are working to increased time pressures, accidental damage to underground cables can cause massive disruptions, which was evident today."
Baird added: "Urgent remedial works were undertaken and service is now restored, with ongoing repairs continuing."
Napier City Business Inc manager Pip Thompson said although the outage had disrupted business in the district, retailers operated to the best of their abilities.
"Today's Vodafone outage is just another hurdle that is testing the resilience of our retailers," she said.
"While this is frustrating, patience and kindness are key and our retailers will be continuing to do the best they can with the technology they have."
It's Vodafone's second recent problem with contractors.
On April 7, the company said roadworks in Kaikoura had damaged an essential fibre cable that connected a large number of South Island households to the internet.
Baird added: "We apologise to any customers who were impacted by these incidents outside of our control."