DP World Australia, which manages nearly half of the goods that flow in and out of the country, said it was looking into possible data breaches as well as testing systems "crucial for the resumption of normal operations and regular freight movement" following a cybersecurity incident.
The Australian government on Sunday described as "serious and ongoing" a cybersecurity incident that forced ports operator DP World Australia to suspend operations at ports in several states since Friday.
The breach halted operations at the containers terminals in Melbourne, Sydney, Brisbane and Western Australia's Fremantle.
"The cyber incident at DP World is serious and ongoing," Home Affairs Minister Clare O'Neil said on social media platform X.
The Australian Federal Police said they were investigating the incident, but declined to elaborate.
Late on Saturday, the National Cyber Security Coordinator Darren Goldie, appointed this year in response to several major data breaches, said the "interruption" was "likely to continue for a number of days and will impact the movement of goods into and out of the country".
In the Asia-Pacific region, Dubai based-DP World says it employs more than 7,000 people and has ports and terminals in 18 locations.