Towns in the lower half of the South Island have lost access to ultrafast broadband services because a contractor inadvertently sliced through fibre cables.
About 1400 customers were affected.
Those impacted are predominantly customers who get their broadband services over fibre rather than copper.
Spark spokesperson Lucy Fullarton said the cut happened in Rakaia this morning.
She said technicians were on site at the moment and were evaluating the situation.
It was not yet known when the cables would be fixed and internet services could resume.
Parts of Timaru, Oamaru, Queenstown, Dunedin and Invercargill were reportedly affected.
Ms Fullarton said people could still use their phones.