DP World Australia, the nation's largest ports operator, says data belonging to current and former employees was accessed in a recent cyber attack. 

The attack earlier this month led to a shutdown of operations in Melbourne, Sydney, Brisbane, and Fremantle, causing significant delays in freight movement. 

The company, responsible for 40 per cent of Australia's maritime freight, experienced a backlog of 30,137 shipping containers.

While operations resumed on November 13, the company only cleared the backlog on November 20, without revealing the method of attack. 

Nicolaj Noes, DP World Australia's executive vice president, has now acknowledged data was accessed in the breach.

“For some of our colleagues, it was their telephone numbers, for some it was their address,” he told the ABC.

“And then for a very few amount of people, there was a little bit more, a copy of a driver's licence, etc.

“The good news is that it's a very small part of our community that has been impacted, and those affected we're working with now on an individual basis.”

Despite suspicions of Russian involvement, the identity of the hackers remains under investigation. 

Noes did not confirm vulnerabilities but admitted hindsight adjustments. 

The Department of Home Affairs is investigating, with DP World collaborating with agencies, including the Australian Cyber Security Centre and the Australian Federal Police.

The threat of further disruptions looms as DP World faces a planned 48-hour work stoppage by employees next week, part of ongoing industrial action related to pay and rosters. 

The Maritime Union of Australia attributes the strikes to breakdowns in negotiations, occurring since mid-November. 

Although DP World cleared the container backlog, Noes warned of continued delays, potentially doubling current estimates. 

The dispute raises concerns of major supply shocks to the national supply chain, impacting Christmas deliveries. 

Meetings between DP World Australia, the Maritime Union, and the Fair Work Commission are scheduled for early December.