Australian officials held multiple crisis meetings during the weekend to respond to a "cyber security incident of national significance," which is still "serious and ongoing," that disrupted operations at key ports across the country. 

The Australian Federal Police announced the opening of an investigation into the alleged cyber-attack, the causes, extent and alleged perpetrators of which are still unclear.

Port operator DP World disrupted internet connectivity at the ports of Sydney, Melbourne, Brisbane and Fremantle to prevent "any ongoing unauthorized access" to its network, according to a spokesman. 

"DP World handles almost 40% of the goods coming in and out of our country," says Home Affairs and Cybersecurity Minister Clare O'Neil.

The disruption has not prevented ships from unloading containers, but the trucks needed to transport them have been unable to enter or leave the terminals, Blake Tierney, a DP World director. 

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The official also said the company has made "significant progress" working with cybersecurity experts and is testing systems "crucial to resuming the regular movement of goods."

"This incident is a reminder of the serious risk that cyber attacks pose to our country and to the vital infrastructure we all depend on," O'Neil adds. 

The "disruption is likely to continue for some days and will impact the flow of goods into and out of the country," national cybersecurity coordinator Darren Goldie says via X (formerly Twitter). 

Australia has been warning of the increase in this type of attacks, which even affected the country's Parliament in 2019.

"Our priority is to assist DP World Australia to resolve the incident, so that they are in a position to restore access to ports operating across the country," Goldie says on X. 

"This disruption is likely to continue for several days and will affect the movement of goods in and out of the country," he indicates.

The disruptions in Sydney, Melbourne, Brisbane and Fremantle threaten to hamper supply chains that were already working to fully recover from the effects of the COVID-19 pandemic. 

The attack also comes as DP World's operations are embroiled in an ongoing strike by the Maritime Union of Australia over wages and better working conditions.