Cellphone coverage was lost to Spark customers during the Waimarama fire as its tower ran out of power.
Unison switched off electricity as a precautionary measure, which resulted in the Spark Tukituki cellphone site running out of their backup power.
A Spark spokeswoman said the cellphone tower's battery backup kicked in but the fires prevented them from being able to access the site to install a generator.
"Before we could get there the battery ran out which meant the Tukituki site was offline for a period of time," she said.
At midday yesterday teams were able to access the site and install a generator, restoring the service.