"We are sorry for the inconvenience this may have caused. Our technical specialists are investigating the root cause to help prevent any recurrence."
Last September, when New Zealand entered daylight saving, prices were delayed when the system had not been adjusted for the changeover.
In January, the NZX was taken to task by the Financial Markets Authority for breaching its market operator obligations in relation to its technology resources after a series of disruptive cyber attacks on the website late last year.
At the time NZX chief executive Mark Peterson said NZX took its market operator obligations seriously.
"We acknowledge the issues that have affected our technology platforms and market participants in 2020," he said at the time.
"NZX accepts that it did not meet the high standards it sets for itself in key areas of technology resources."
"We also agree that improvements are required and we are committed to delivering these improvements via an action plan that will be agreed with the FMA."
For the first four days of a sustained DDoS (distributed denial of service) attack that began on August 26, NZX suspended trading on the basis that the attack did not target its trading platform.