Tauranga City Council had to shut down its entire computer system after receiving a cyber threat from overseas yesterday.
The council issued an advisory that its online and email services were down and the cyber threat was confirmed in the afternoon. The threat meant anyone attempting to pay a bill online was unable to do so.
Council communications spokeswoman Aimee Driscoll said the threat was known as a cryptolock, which essentially encrypts and locks a computer system.
"To protect our system we shut everything down straight away and referred to this as a lockdown," she said.
"We were able to isolate the threat and test our system and bring it back due to the quick actions of our ICT (information communication technology) team."
Ms Driscoll said the council's network security was constantly monitored through both a third party "as well as our own internal security".
"It was through this we identified the threat. We were able to isolate it."
The lockdown lasted most of the day.
Ms Driscoll said the threat, when successful, takes files and locks things down.
"Once it is locked in, you don't always get the files back but - because we isolated it so quickly - it didn't managed to get into the system."
The council's online services are back up and running.