Stock exchange operator NZX halts trading early following offshore cyber attack

Stock exchange operator NZX halted trading its cash markets early this afternoon after an offshore cyber attack oversaturated its network with high internet traffic.

File picture. Source: Supplied

Trading was stopped at approximately 3.57pm after it experienced a "volumetric distributed denial of service (DDoS) attack" which impacted its system connectivity, Spark and NZX said today in a joint statement.

The attack "aims to disrupt service by saturating a network with significant volumes of internet traffic," the statement read.

"The attack was able to be mitigated and connectivity has now been restored for NZX."

It comes as the S&P/NZX 50 Index closed today at 11,993.18 points, up 0.6 per cent.