Retailers will be anxiously opening their stores on Saturday morning, hoping a global IT outage has been resolved, Retail NZ says.

The outage - caused by an update to a piece of software run by US cybersecurity firm CrowdStrike - caused Windows computers around the world to crash on Friday, cancelling flights, disrupting transactions and stopping people from accessing their online banking accounts.

People were left stranded at petrol stations because they had no cash to pay for fuel, while stores were forced to close their doors.

Retail NZ chief executive Carolyn Young told RNZ many stores would be "opening first thing in the morning and looking for this to be resolved".

"Largely it's out of our hands," she said.

The outage would have an impact on business confidence, which was already shaky thanks to the high cost of living and the official cash rate, she said.

CrowdStrike deployed a fix for the software on Friday evening, but tech experts have said it could take several days for systems worldwide to be running as normal.

Cybersecurity researcher Kevin Beaumont told BBC News affected computers all needed to be started in safe mode to remove the faulty update.

"This is incredibly time-consuming and will take organisations days to do at scale. Essentially we have one of the world's highest impact IT incidents caused by a cyber-security vendor."

this story was originally posted on RNZ News