Scores of customers have posted complaints on the company's Facebook page.
Jo Smith said: "Well I had no internet or home phone here in Oamaru. Now have internet back on but no home phone. Checked your website which says no major outages, which is obviously wrong as others are obviously having problems too. What is the point having it if it isn't kept up to date?"
One person showed a message from Vodafone which appeared when he tried to log on to the page. It read: "Sorry we are currently experiencing technical difficulties."
Heather Taylor said: "No net here in Otaki either. Massive wait to speak to someone who couldn't tell me when it'd be sorted."
Others saw the funny side.
Matthew Tyrrell said: "I really hope the kids of NZ survive this morning with no Netflix. Maybe someone will have to, you know, talk with them or something? Oh, the humanity."
Vodafone have also posted on their Facebook page alerting the outage to their customers.