The government's cyber emergency response team is urging people to keep their computer software up-to-date, as the threat of cyber-attacks increases.
Hundreds of thousands of computers around the world have been infected with a malicious software called WannaCry that encrypts files.
The hackers are demanding money in the form of the digital currency Bitcoin to unfreeze the infected computers.
A UK security researcher known as MalwareTech, who helped limit the ransomware attack, has warned of "another one [cyber-attack] coming ... quite likely on Monday".
More than 125,000 computer systems have been hit by the global virus which spread to 100 countries, including Spain, France, Russia and the United Kingdom.
The New Zealand government's computer emergency response team (CERT) is looking into the attack here.
Its operations manager Declan Ingram said people could take steps to keep their computers and personal information safe.
"With all ransomware attacks we recommend that people always have their operating systems and their applications completely patched and up-to-date, making sure that they have all of their files backed up and stored off-line and of course ensuring that their firewalls and anti-viruses are all installed and fully functional as well."
Mr Ingram said his team was yet to hear from any New Zealanders affected by the ransomware though this country is listed among the 104 nations mappers say have been hit by the malware.
The deputy chief executive at Internet New Zealand, Andrew Cushen, said software behind a ransomware wasn't difficult to build and protecting against it required a simple update.
"Infection can be relatively easy, it can be done through opening up the wrong file that's been emailed to you from someone, or by opening a PDF or even sharing a network, in this case from someone that's already infected."
There have been reports of infections in as many as 100 countries, a live-tracking map of the attack showed.
Ministry of Health officials have been briefed by police about the ransomware attacks.
Police said they had not been made aware of any attacks in New Zealand and the briefing to the ministry was a precaution.
The attack is so unprecedented that Microsoft has quickly changed its policy on supporting outdated operating systems, announcing security fixes will be available for free for the older Windows systems still used by millions of individuals and smaller businesses.
RNZ / BBC