The Australian Information Commissioner is suing Facebook in the United States and Ireland over alleged privacy breaches of 311,000 Australian users.

Facebook lost the first round of legal proceedings in March and its American branch is trying to get out of the case.

Information commissioner Angelene Falk is bracing for the next round of legal bouts.

Independent senator Rex Patrick used a Senate estimates hearing on Thursday to raise concerns about delay tactics the case could face.

"A strategy that gets played out in places like Europe, these matters get appealed, interlocutories, just grinding down," he said.

"And if I look at the OAIC's budget I suspect there might be a strategy here to just run this down."

Attorney-General's Department secretary Chris Moraitis said it was likely the case would be drawn out.

"We work very closely with the office to ensure they have the resources they need to pursue this," he said.

"Depending on how long this process continues, we'll continue to engage very closely with the office because this is a matter of some significance to all of us."

The office has $27 million available over the next two years.

Facebook is accused of disclosing the personal information of Australian users to a third-party app between March 2014 and May 2015.

User data collected by the app was later used for political profiling.

Cambridge Analytica rose to global prominence in 2018 when it was linked to a breach using Facebook user data for political advertising.

Ms Falk said the proceedings related to serious, repeated interferences with the privacy of Australians.

Australian Associated Press