Millions of Kiwis using Wi-Fi internet networks at home or work could be vulnerable to a newly discovered flaw in the technology, the government is warning.
Cert NZ said the flaw could affect almost all devices connected to a Wi-Fi network, including computers, phones, routers and smart TVs.
It could allow hackers to eavesdrop on or hijack devices using a wireless network, it warned.
Findings of the flaw, known as Krack (Key Reinstallation Attack) were published by a Belgian security expert and have prompted worldwide warnings, including from the US government's cybersecurity arm.
However, so far Cert NZ was yet to receive a report of "Krack affecting New Zealanders", a spokeswoman said.
To protect against the flaw, Kiwis should run software updates on all their devices with some companies, such as Microsoft, already releasing security patches that have resolved the Wi-Fi issue, Cert NZ said.
Internet users should also avoid using Wi-Fi when possible and physically plug their devices in with ethernet cables.
A spokeswoman for internet service provider Spark said it became aware overnight of the security vulnerability "that has the potential to put all Wi-Fi networks, and the devices that access those networks, at risk of being compromised".
However, she said Spark was not aware of any of its customers being compromised by the vulnerability.
"Spark is liaising with device manufacturers as a matter of urgency to understand when they will have patches available for their devices," she said.
She said a hacker would need to be within Wi-Fi range to exploit the flaw and would not be able to access encrypted traffic, such as that passing between devices and most banking websites.