Almost all of the mobile, broadband and landline services that were out have now been restored for Spark customers across Canterbury and Otago.
The outages were due to flooding and slips across the South Island affecting Spark's network.
The telecommunication company confirmed in a statement that the services have been fixed by using a workaround - spare fibre strands and additional cables.
But, Spark has also said services are still vulnerable because they are relying on a damaged cable, which could be affected by changing weather conditions.
All Spark mobile, landline and broadband customers south of Ashburton were affected.
The wild weather yesterday forced the Timaru District Council to declare a state of emergency, with residents near the flooded Rangitata River ordered to evacuate.
The outage at one point caused disruption to 159 cell sites servicing the South Island. Spark will continue to monitor the situation.